The DOI matches its Crossref record; 59 of the 60 references it cites were found in a registry or an index, and 1 are not checked yet; 20 of the 49 sources its claims cite were checked for support.
Packaging Capacity of Adeno-Associated Virus Serotypes: Impact of Larger Genomes on Infectivity and Postentry Steps
Open accessAbstract
The limited packaging capacity of adeno-associated virus (AAV) precludes the design of vectors for the treatment of diseases associated with larger genes. Autonomous parvoviruses, such as minute virus of mice and B19, while identical in size (25 nm), are known to package larger genomes of 5.1 and 5.6 kb, respectively, compared to AAV genomes of 4.7 kb. One primary difference is the fact that wild-type (wt) AAV utilizes three capsid subunits instead of two to form the virion shell. In this study, we have characterized the packaging capacity of AAV serotypes 1 through 5 with and without the Vp2 subunit. Using reporter transgene cassettes that range in size from 4.4 to 6.0 kb, we determined that serotypes 1 through 5 with and without Vp2 could successfully package, replicate in, and transduce cells. Dot blot analysis established that packaging efficiency was similar for all vector cassettes and that the integrity of encapsidated genomes was intact regardless of size. Although physical characterization determined that virion structures were indistinguishable from wt, transduction experiments determined that all serotype vectors carrying larger genomes (5.3 kb and higher) transduced cells less efficiently (within a log) than AAV encapsidating wt size genomes. This result was not unique to reporter genes and was observed for CFTR vector cassettes ranging in size from 5.1 to 5.9 kb. No apparent advantage in packaging efficiency was observed when Vp2 was present or absent from the virion. Further analysis determined that a postentry step was responsible for the block in infection and specific treatment of cells upon infection with proteasome inhibitors increased transduction of AAV encapsidating larger DNA templates to wt levels, suggesting a preferential degradation of virions encapsidating larger-than-wt genomes. This study illustrates that AAV is capable of packaging and protecting recombinant genomes as large as 6.0 kb but the larger genome-containing virions are preferentially degraded by the proteasome and that this block can be overcome by the addition of proteasome inhibitors.
Verified 2026-10-28 · 1 reference not checked yet
Overview
AI snapshot
Written from the paper’s full text.
TL;DR
AAV serotypes 1 through 5, with or without Vp2, can package and protect recombinant genomes as large as 6.0 kb, but vectors carrying genomes larger than about 5.2 kb transduce cells less efficiently. The reduced infectivity is postentry and can be overcome by proteasome inhibition, suggesting preferential proteasome degradation of virions containing larger genomes.
Key findings
- Packaging efficiency was similar across all vector cassettes and serotypes: dot blot titers for the largest cassettes were 3 × 10⁶ to 9 × 10⁷ viral genomes/μl versus 6 × 10⁶ to 1 × 10⁸ viral genomes/μl for wild-type-size cassettes, with no apparent advantage when Vp2 was absent.
- AAV serotypes 1 through 5 packaged and protected genomes as large as 6 kb, and alkaline agarose/Southern analysis showed intact encapsidated genomes regardless of size.
- Transduction was reduced for genomes of 5.3 kb and higher, with CAT assays showing a consistent 3- to 7-fold difference between wild-type-size and K/L genomes; CFTR cassettes from 5.1 to 5.9 kb were also packaged and produced a 450-bp RT-PCR product.
- The proteasome inhibitor LLnL increased transduction of AAV encapsidating E, K, and L genomes by 1.1-, 2.2-, and 5.7-fold, respectively, at 40 μM, restoring K to wild-type levels and L to near wild-type levels (less than twofold difference).
Methods
- Recombinant AAV was produced by calcium phosphate triple plasmid transfection in 293 cells using pXR1–pXR5 helper plasmids or Vp2-knockout ACA1–ACA5 plasmids, plus pAVCNst CAT packaging cassettes D through L (4,461–6,019 bp) or CFTR cassettes ranging from 5.1 to 5.9 kb.
- Vector characterization included dot blot titration, alkaline agarose gel/Southern analysis of extracted virion genomes, Hirt extraction replication assays, electron microscopy, and CAT transduction assays in HeLa or COS-1 cells infected at 500 viral genomes/cell with adenovirus dl309 at an MOI of 5.
- Additional experiments tested CsCl-, iodixanol-, and FPLC-heparin-purified vectors, temperature stability, CFTR mRNA detection by RT-PCR, and treatment with the proteasome inhibitor LLnL.
Limitations
- The paper states that the functional relevance of Vp2 remains unresolved, that more sensitive real-time PCR would be needed to directly compare CFTR mRNA levels with and without LLnL, and that further CFTR vector studies are ongoing but beyond the scope of the study.
- The paper notes that fitness of larger-genome viruses was not tested because it is not relevant for vector production, which involves only one round of infection rather than cycling.
- Evident from the text: many packaging and transduction screens used crude lysates and small-scale productions, and the authors note preparation-to-preparation variation in titer and infectious-to-noninfectious particle ratios, which they controlled by using duplicate assays with separate viral preparations.
Model-written summary. Check it against the paper before relying on it.
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Claims the paper makes
33 Own result · 16 Own interpretation · 8 Partly supported · 8 No full text of the sources · 5 Supported so far · 3 Own method · 2 No basis given · 1 Supported · 1 Mixed support · 1 Couldn’t confirm · 1 Not checked yet · accuracy not yet measured
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“It was recently determined that AAV capsids are ubiquitinated, marking them for degradation by the proteasome (Fig.8IV) (50), adding more support to the notion that proteasomes in the cytoplasm act as barriers to AAV infection.”
What the sources say
- Partly supportedcites [50] Yan, Z., R. Zak, G. W. Luxton, T. C. Ritchie, U. Bantel-Schaal, and J. F. Engelhardt. 2002. Ubiquitination of both adeno-associated virus type 2 and 5 capsid proteins affects the transduction efficiency of recombinant vectors. J. Virol. 76:2043-2053. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Abstract reports that AAV-2 and AAV-5 capsids are ubiquitinated and that proteasome inhibitors increase transduction. The discussion (section labeled “4 μM Z-LLL”; page unavailable) says the consequence of ubiquitination is undefined and finds no evidence that the inhibitors improve transduction by preventing degradation of internalized virions. Thus the paper supports a proteasome-related barrier to transduction, but not the asserted degradation mechanism or its specific location in the cytoplasm. (LLM, conf=0.88)
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“It was recently determined that AAV capsids are ubiquitinated, marking them for degradation by the proteasome (Fig.8IV) (50), adding more support to the notion that proteasomes in the cytoplasm act as barriers to AAV infection.”
What the sources say
- Partly supportedcites [50] Yan, Z., R. Zak, G. W. Luxton, T. C. Ritchie, U. Bantel-Schaal, and J. F. Engelhardt. 2002. Ubiquitination of both adeno-associated virus type 2 and 5 capsid proteins affects the transduction efficiency of recombinant vectors. J. Virol. 76:2043-2053. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Fig. 4 results (section labeled “4 μM Z-LLL”; page not provided) demonstrate ubiquitination of AAV-2 and AAV-5 capsid proteins in HeLa cells. The same section describes proteasomal degradation as a possibility, not an established consequence of that ubiquitination; it also reports no increase in viral-genome stability with proteasome inhibition. Thus the claim overstates the proposed degradation mechanism. (LLM, conf=0.88)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Partly supported
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“It is important to note that ordered DNA structure has been identified in crystal structures for canine parvovirus (CPV) and MVM, illustrating that the genome is bound to the interior of the capsid by a specific nucleotide-capsid interaction (1, 7, 47, 49).”
What the sources say
- Supportedcites [1] Agbandje-McKenna, M., A. L. Llamas-Saiz, F. Wang, P. Tattersall, and M. G. Rossmann. 1998. Functional implications of the structure of the murine parvovirus, minute virus of mice. Structure 6:1369-1381. [DOI] [PubMed] [Google Scholar] source
The Results and discussion report ordered DNA nucleotides in MVMi, ten with a similar structure in CPV. The same section says that their ordering and conserved base-binding sites identify a DNA-recognition site on the capsid interior, supporting the cited claim. (LLM, conf=0.88)
- Not matchedcites [7] Chapman, M. S., and M. G. Rossmann. 1995. Single-stranded DNA-protein interactions in canine parvovirus. Structure 3:151-162. [DOI] [PubMed] [Google Scholar]
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not checked — no full text of the sourcecites [47] Wu, H., and M. G. Rossmann. 1993. The canine parvovirus empty capsid structure. J. Mol. Biol. 233:231-244. [DOI] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [49] Xie, Q., and M. S. Chapman. 1996. Canine parvovirus capsid structure, analyzed at 2.9 A resolution. J. Mol. Biol. 264:497-520. [DOI] [PubMed] [Google Scholar] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Supported
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Proteasome inhibitors have been described in numerous studies to increase the transduction of rAAV postentry of the cell, suggesting that proteasomes are a barrier for intracellular trafficking (11, 51).”
What the sources say
- Not checked — no full text of the sourcecites [11] Douar, A. M., K. Poulard, D. Stockholm, and O. Danos. 2001. Intracellular trafficking of adeno-associated virus vectors: routing to the late endosomal compartment and proteasome degradation. J. Virol. 75:1824-1833. [DOI] [PMC free article] [PubMed] [Google Scholar] source
- Supportedcites [51] Yan, Z., R. Zak, Y. Zhang, W. Ding, S. Godwin, K. Munson, R. Peluso, and J. F. Engelhardt. 2004. Distinct classes of proteasome-modulating agents cooperatively augment recombinant adeno-associated virus type 2 and type 5-mediated transduction from the apical surfaces of human airway epithelia. J. Virol. 78:2863-2874. [DOI] [PMC free article] [PubMed] [Google Scholar] source
The Results report that proteasome-modulating agents increased nuclear accumulation of rAAV DNA after infection and facilitated its movement to the nucleus. This supports the citing sentence’s inference that proteasome activity can impede postentry intracellular trafficking of rAAV; the Discussion notes that the precise mechanism remains unclear. No page number was provided in our copy. (LLM, conf=0.91)
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Proteasome inhibitors have been described in numerous studies to increase the transduction of rAAV postentry of the cell, suggesting that proteasomes are a barrier for intracellular trafficking (11, 51).”
What the sources say
- Not checked — no full text of the sourcecites [11] Douar, A. M., K. Poulard, D. Stockholm, and O. Danos. 2001. Intracellular trafficking of adeno-associated virus vectors: routing to the late endosomal compartment and proteasome degradation. J. Virol. 75:1824-1833. [DOI] [PMC free article] [PubMed] [Google Scholar] source
- Supportedcites [51] Yan, Z., R. Zak, Y. Zhang, W. Ding, S. Godwin, K. Munson, R. Peluso, and J. F. Engelhardt. 2004. Distinct classes of proteasome-modulating agents cooperatively augment recombinant adeno-associated virus type 2 and type 5-mediated transduction from the apical surfaces of human airway epithelia. J. Virol. 78:2863-2874. [DOI] [PMC free article] [PubMed] [Google Scholar] source
The Results (page unavailable) report that the proteasome inhibitors LLnL and doxorubicin enhanced nuclear accumulation of rAAV DNA after infection. The authors interpret this as evidence that the ubiquitin/proteasome system controls intracellular processing, supporting the claim of a postentry effect. (LLM, conf=0.92)
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Figure 3 (top) illustrates that the AAV2 D through L viruses can infect and deliver their respective genomes to the nuclei of 293 cells, albeit at a decreased level for the K and L vectors with respect to the others.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Infectivity/transduction were restored to wt or near wt levels for AAV encapsidating the 5.3- and 6-kb genomes, respectively, shifting the balance from proteasome degradation to nuclear accumulation, resulting in increased transduction (Fig. 6).”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Based on our studies, it was demonstrated that AAV is capable of packaging vector genomes as large as 6 kb or approximately 130% the size of the wt genome with similar efficiency.”
- Also stated in: § DISCUSSION · hedged
“This study suggests that AAV is capable of encapsidating genomes as large as 6 kb with similar efficiencies as genomes of wt size (Table 1 and Fig. 2).”
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Also stated in: § DISCUSSION · hedged
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, these larger-genome-containing virions were found to be less infectious (within a log) than those containing genomes of wt size (Fig. 3).”
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Little to no transduction was detected with any vector when exposed to 65°C (data not shown).”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Probably not a substantial claim. 17
- It may state two separate claims as one. 28
Some cited sources support this claim and some don’t — read each source’s verdict below.
In the paper
“Studies have been carried out by a number of groups (11, 22, 50, 51) illustrating that drugs/chemicals such as bafilomycin A, brefeldin A, and MG-132 augment rAAV transduction by acting on the level of endosome acidification, early-to-late endosome transition, and proteasome activity, respectively.”
What the sources say
- Not checked — no full text of the sourcecites [11] Douar, A. M., K. Poulard, D. Stockholm, and O. Danos. 2001. Intracellular trafficking of adeno-associated virus vectors: routing to the late endosomal compartment and proteasome degradation. J. Virol. 75:1824-1833. [DOI] [PMC free article] [PubMed] [Google Scholar] source
- Disputedcites [22] Hansen, J., K. Qing, and A. Srivastava. 2001. Adeno-associated virus type 2-mediated gene transfer: altered endocytic processing enhances transduction efficiency in murine fibroblasts. J. Virol. 75:4080-4090. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Results report that bafilomycin A inhibits endosomal acidification but significantly decreased AAV transduction in 293 cells and had little effect in NIH 3T3 cells—the opposite of the claimed augmentation. The supplied passages do not establish the claimed effects of brefeldin A or MG-132. (LLM, conf=0.89)
Checked by a reasoning model — may be wrong.
- Supportedcites [50] Yan, Z., R. Zak, G. W. Luxton, T. C. Ritchie, U. Bantel-Schaal, and J. F. Engelhardt. 2002. Ubiquitination of both adeno-associated virus type 2 and 5 capsid proteins affects the transduction efficiency of recombinant vectors. J. Virol. 76:2043-2053. [DOI] [PMC free article] [PubMed] [Google Scholar] source
The source identifies Z-LLL as MG132 (methods passage, indexed under Abstract). Its transduction results (Table 1 passage, indexed under Abstract) report that Z-LLL, a proteasome inhibitor, augmented rAAV transduction in all four cell types tested. This supports the MG-132/proteasome portion of the sentence; the other drugs are not attributed specifically to this source among the four citations. (LLM, conf=0.91)
- Partly supportedcites [51] Yan, Z., R. Zak, Y. Zhang, W. Ding, S. Godwin, K. Munson, R. Peluso, and J. F. Engelhardt. 2004. Distinct classes of proteasome-modulating agents cooperatively augment recombinant adeno-associated virus type 2 and type 5-mediated transduction from the apical surfaces of human airway epithelia. J. Virol. 78:2863-2874. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The paper identifies MG132 (Z-LLL) as a proteasome inhibitor that can enhance rAAV transduction (introductory passage; Results). It does not address the claimed effects of bafilomycin A on endosome acidification or brefeldin A on early-to-late endosome transition. No page numbers are available in our copy. (LLM, conf=0.86)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The early steps of AAV infection involve attachment to a variety of cell surface receptors such as HSPG, FGFR, αvβ5 integrin, and hepatocyte growth factor receptor (c-Met) (Fig. 8I) (9, 25, 31, 39, 40), followed by clathrin-dependent endocytosis (Fig.8II).”
What the sources say
- Partly supportedcites [9] Di Pasquale, G., B. L. Davidson, C. S. Stein, I. Martins, D. Scudiero, A. Monks, and J. A. Chiorini. 2003. Identification of PDGFR as a receptor for AAV-5 transduction. Nat. Med. 9:1306-1312. [DOI] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The introduction lists HSPG, FGFR-1 and αvβ5 integrin among factors expressed by AAV-2-permissive cells, but does not identify c-Met as an AAV receptor. The Discussion also reports clathrin-coated-vesicle entry for AAV-5, rather than establishing that route for AAV generally. Page numbers are unavailable in our copy. (LLM, conf=0.86)
- Partly supportedcites [25] Kashiwakura, Y., K. Tamayose, K. Iwabuchi, Y. Hirai, T. Shimada, K. Matsumoto, T. Nakamura, M. Watanabe, K. Oshimi, and H. Daida. 2005. Hepatocyte growth factor receptor is a coreceptor for adeno-associated virus type 2 infection. J. Virol. 79:609-614. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The opening summary identifies HSPG as the primary attachment receptor and FGFR1, αvβ5 integrin, and c-Met as AAV2 coreceptors. The Discussion also reports AAV2 internalization from clathrin-coated pits. However, the Results say c-Met did not increase AAV2 cell attachment, so describing c-Met as an attachment receptor is not supported. (LLM, conf=0.88)
- Not checked — no full text of the sourcecites [31] Qing, K., C. Mah, J. Hansen, S. Zhou, V. Dwarki, and A. Srivastava. 1999. Human fibroblast growth factor receptor 1 is a co-receptor for infection by adeno-associated virus 2. Nat. Med. 5:71-77. [DOI] [PubMed] [Google Scholar] source
- Not matchedcites [39] Summerford, C., J. S. Bartlett, and R. J. Samulski. 1999. AlphaVbeta5 integrin: a co-receptor for adeno-associated virus type 2 infection. Nat. Med. 5:78-82. [DOI] [PubMed] [Google Scholar]
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not matchedcites [40] Summerford, C., and R. J. Samulski. 1998. Membrane-associated heparan sulfate proteoglycan is a receptor for adeno-associated virus type 2 virions. J. Virol. 72:1438-1445. [DOI] [PMC free article] [PubMed] [Google Scholar]
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“In contrast, the N termini of Vp1 and Vp2 of AAV are located within the virion (27, 46, 48).”
What the sources say
- Partly supportedcites [27] Kronenberg, S., J. A. Kleinschmidt, and B. Bottcher. 2001. Electron cryo-microscopy and image reconstruction of adeno-associated virus type 2 empty capsids. EMBO Rep. 2:997-1002. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Results (page not provided) conclude that VP1 and VP2 N-terminal extensions are likely inside AAV2 empty capsids, in contrast to evidence of outward extension in MVM and B19. The source presents the AAV2 location as an inference, not a directly determined fact, and does not establish it for AAV virions generally. (LLM, conf=0.88)
- Partly supportedcites [46] Wobus, C. E., B. Hugle-Dorr, A. Girod, G. Petersen, M. Hallek, and J. A. Kleinschmidt. 2000. Monoclonal antibodies against the adeno-associated virus type 2 (AAV-2) capsid: epitope mapping and identification of capsid domains involved in AAV-2-cell interaction and neutralization of AAV-2 infection. J. Virol. 74:9281-9293. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Results map A1 and A69 epitopes to N-terminal regions of VP1 and VP2. The Discussion says these epitopes become partially masked during AAV-2 capsid assembly and describes some regions as probably buried; it does not establish that both N termini are located within the virion. Page numbers are unavailable in our copy. (LLM, conf=0.83)
- Not checked — no full text of the sourcecites [48] Xie, Q., W. Bu, S. Bhatia, J. Hare, T. Somasundaram, A. Azzi, and M. S. Chapman. 2002. The atomic structure of adeno-associated virus (AAV-2), a vector for human gene therapy. Proc. Natl. Acad. Sci. USA 99:10405-10410. [DOI] [PMC free article] [PubMed] [Google Scholar] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Partly supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“One primary difference is the fact that wild-type (wt) AAV utilizes three capsid subunits instead of two to form the virion shell.”
- Also stated in: § Abstract · plain
“The virion is composed of three capsid proteins, Vp1, Vp2, and Vp3, produced in a 1:1:10 ratio from the same open reading frame but from differential splicing (Vp1) and alternative translational start sites (Vp2 and Vp3, respectively) (30).”
What the sources say
- Supportedcites [30] Muralidhar, S., S. P. Becerra, and J. A. Rose. 1994. Site-directed mutagenesis of adeno-associated virus type 2 structural protein initiation codons: effects on regulation of synthesis and biological activity. J. Virol. 68:170-176. [DOI] [PMC free article] [PubMed] [Google Scholar] source
The cited sentence attributes the use of three capsid subunits to wild-type AAV. The paper describes three AAV2 capsid proteins (A, B, and C) in its opening section (p. 1) and discusses their roles in virion assembly in the Results (p. 4). The ratio in the supplied paraphrase is not part of the citing sentence assessed here. (LLM, conf=0.91)
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Also stated in: § Abstract · plain
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Use of proteasome inhibitors such as MG-132 and LLnL have been shown to increase transduction, providing evidence that after endosome escape, AAV must elude proteasomes in the cytoplasm while traversing to the nucleus (Fig. 8IV and V) (11, 51).”
What the sources say
- Not checked — no full text of the sourcecites [11] Douar, A. M., K. Poulard, D. Stockholm, and O. Danos. 2001. Intracellular trafficking of adeno-associated virus vectors: routing to the late endosomal compartment and proteasome degradation. J. Virol. 75:1824-1833. [DOI] [PMC free article] [PubMed] [Google Scholar] source
- Partly supportedcites [51] Yan, Z., R. Zak, Y. Zhang, W. Ding, S. Godwin, K. Munson, R. Peluso, and J. F. Engelhardt. 2004. Distinct classes of proteasome-modulating agents cooperatively augment recombinant adeno-associated virus type 2 and type 5-mediated transduction from the apical surfaces of human airway epithelia. J. Virol. 78:2863-2874. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The introductory passage identifies Z-LLL as MG132 and reports that it and LLnL enhance rAAV transduction; the Results also show that LLnL increases transduction and nuclear accumulation of viral DNA. But the Discussion says how these agents alter rAAV interactions with the proteasome remains unclear. The paper does not establish that, after escaping endosomes, AAV must elude cytoplasmic proteasomes on its way to the nucleus. (LLM, conf=0.88)
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Once AAV is in the cytoplasm en route to the nucleus, the virion is thought to be ubiquitinated (Fig. 8IV), thereby being targeted for degradation by the proteasome.”
What the sources say
- Partly supportedcites [50] Yan, Z., R. Zak, G. W. Luxton, T. C. Ritchie, U. Bantel-Schaal, and J. F. Engelhardt. 2002. Ubiquitination of both adeno-associated virus type 2 and 5 capsid proteins affects the transduction efficiency of recombinant vectors. J. Virol. 76:2043-2053. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
In the section labeled “4 μM Z-LLL” (page unavailable), the paper reports ubiquitination of AAV-2 and AAV-5 capsid proteins in infected HeLa cells. It treats proteasomal degradation of ubiquitinated virions as a possibility, not an established consequence: intact virions were poor substrates for ubiquitination in vitro, and proteasome inhibition did not increase intracellular viral DNA stability. The claimed sequence of an intact virion being ubiquitinated en route to the nucleus and thereby targeted for degradation is therefore not established by this source. (LLM, conf=0.87)
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“While Vp1 is required for infectivity, Vp2 has been shown to be nonessential (44).”
What the sources say
- Partly supportedcites [44] Warrington, K. H., Jr., O. S. Gorbatyuk, J. K. Harrison, S. R. Opie, S. Zolotukhin, and N. Muzyczka. 2004. Adeno-associated virus type 2 VP2 capsid protein is nonessential and can tolerate large peptide insertions at its N terminus. J. Virol. 78:6595-6609. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Discussion says VP2 is nonessential and VP1 is required for *efficient* viral infectivity. But it also reports that particles lacking VP1 have low infectivity, so the unqualified statement that VP1 is required for infectivity overstates the finding. (LLM, conf=0.88)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
- Partly supported
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“A phospholipase domain, essential for viral infectivity, has been identified in the unique N terminus of Vp1 (19, 53).”
What the sources say
- Not checked — no full text of the sourcecites [19] Girod, A., C. E. Wobus, Z. Zadori, M. Ried, K. Leike, P. Tijssen, J. A. Kleinschmidt, and M. Hallek. 2002. The VP1 capsid protein of adeno-associated virus type 2 is carrying a phospholipase A2 domain required for virus infectivity. J. Gen. Virol. 83:973-978. [DOI] [PubMed] [Google Scholar] source
- Supportedcites [53] Zadori, Z., J. Szelei, M. C. Lacoste, Y. Li, S. Gariepy, P. Raymond, M. Allaire, I. R. Nabi, and P. Tijssen. 2001. A viral phospholipase A2 is required for parvovirus infectivity. Dev. Cell 1:291-302. [DOI] [PubMed] [Google Scholar] source
The Results identify phospholipase A2 motifs and activity in VP1up, the VP1-unique region. The Discussion states that viral phospholipase A2 is critical for infectivity, and the Results report that mutations reducing its activity also reduce infectivity (page numbers unavailable). (LLM, conf=0.94)
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The cited sources that could be checked couldn’t confirm or dispute this claim.
In the paper
“However, ordered DNA has yet to be discovered in the crystal structures solved for AAV, suggesting that DNA-capsid interactions may be lacking or not as important for AAV (42, 48).”
What the sources say
- Could not verifycites [42] Walters, R. W., M. Agbandje-McKenna, V. D. Bowman, T. O. Moninger, N. H. Olson, M. Seiler, J. A. Chiorini, T. S. Baker, and J. Zabner. 2004. Structure of adeno-associated virus serotype 5. J. Virol. 78:3361-3371. [DOI] [PMC free article] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The Methods (p. 2) say the AAV5 reconstruction used images of empty capsids, and the Results (p. 3) describe a cryo-EM reconstruction, not an AAV5 crystal structure. Searches for ordered DNA and DNA–capsid interactions found no passage stating whether ordered DNA appears in AAV crystal structures or drawing the claimed inference about the importance of those interactions. (LLM, conf=0.78)
- Not checked — no full text of the sourcecites [48] Xie, Q., W. Bu, S. Bhatia, J. Hare, T. Somasundaram, A. Azzi, and M. S. Chapman. 2002. The atomic structure of adeno-associated virus (AAV-2), a vector for human gene therapy. Proc. Natl. Acad. Sci. USA 99:10405-10410. [DOI] [PMC free article] [PubMed] [Google Scholar] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Could not verify
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Recently, split vector systems, exploiting head-to-tail concatamerization formation, have been developed to circumvent the small packaging capacity of AAV genomes (13-16, 41, 52).”
What the sources say
- Not checked — no full text of the sourcecites [13] Duan, D., Y. Yue, and J. F. Engelhardt. 2003. Dual vector expansion of the recombinant AAV packaging capacity. Methods Mol. Biol. 219:29-51. [DOI] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [14] Duan, D., Y. Yue, and J. F. Engelhardt. 2001. Expanding AAV packaging capacity with trans-splicing or overlapping vectors: a quantitative comparison. Mol. Ther. 4:383-391. [DOI] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [15] Duan, D., Y. Yue, Z. Yan, and J. F. Engelhardt. 2000. A new dual-vector approach to enhance recombinant adeno-associated virus-mediated gene expression through intermolecular cis activation. Nat. Med. 6:595-598. [DOI] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [16] Duan, D., Y. Yue, Z. Yan, and J. F. Engelhardt. 2003. Trans-splicing vectors expand the packaging limits of adeno-associated virus for gene therapy applications. Methods Mol. Med. 76:287-307. [DOI] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [41] Sun, L., J. Li, and X. Xiao. 2000. Overcoming adeno-associated virus vector size limitation through viral DNA heterodimerization. Nat. Med. 6:599-602. [DOI] [PubMed] [Google Scholar] source
- Supportedcites [52] Yan, Z., Y. Zhang, D. Duan, and J. F. Engelhardt. 2000. Trans-splicing vectors expand the utility of adeno-associated virus for gene therapy. Proc. Natl. Acad. Sci. USA 97:6716-6721. [DOI] [PMC free article] [PubMed] [Google Scholar] source
The Results describe a dual-vector approach designed to deliver a gene exceeding the capacity of a single AAV virion through head-to-tail circular concatamers. The Discussion says the study used two trans-splicing vectors to enable delivery of a large transgene despite AAV’s small packaging size. (LLM, conf=0.94)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Data based on autonomous parvoviruses suggest that, prior to escaping the endosome, the virion is thought to undergo conformational changes, leading to the exposure of the unique N terminus of Vp1, necessary for escape (Fig. 8III) (5, 33).”
What the sources say
- Partly supportedcites [5] Carreira, A., M. Menendez, J. Reguera, J. M. Almendral, and M. G. Mateu. 2004. In vitro disassembly of a parvovirus capsid and effect on capsid stability of heterologous peptide insertions in surface loops. J. Biol. Chem. 279:6517-6525. [DOI] [PubMed] [Google Scholar] sourceExperimental — accuracy not yet measured
The introductory passage reports that heating minute virus of mice virions exposed the VP1 N terminus, and the Discussion describes a conformational rearrangement in VP2-only capsids. The paper does not establish that VP1 exposure occurs before endosomal escape or is necessary for that escape; its preliminary evidence concerns infectivity and possible uncoating in vivo. Page numbers are unavailable in our copy. (LLM, conf=0.85)
- Not checked — no full text of the sourcecites [33] Reguera, J., A. Carreira, L. Riolobos, J. M. Almendral, and M. G. Mateu. 2004. Role of interfacial amino acid residues in assembly, stability, and conformation of a spherical virus capsid. Proc. Natl. Acad. Sci. USA 101:2724-2729. [DOI] [PMC free article] [PubMed] [Google Scholar] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
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- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Partly supported
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Replicated monomer products can be detected for all of the virally delivered packaging constructs, but the replication dimer product for the L cassette is not detected at these exposure times.”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Using reporter transgene cassettes that range in size from 4.4 to 6.0 kb, we determined that serotypes 1 through 5 with and without Vp2 could successfully package, replicate in, and transduce cells.”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It is clear that AAV is capable of encapsidating each CFTR cassette in its entirety and infecting target cells (Fig. 7, left lanes 3, 4, and 5).”
boosteddirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The AAV2 E and K vectors were resistant to the 37 and 45°C temperatures based on transduction but were negatively affected (twofold decrease) by the 56°C temperature.”
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The inability of these viruses to infect cells efficiently was not due to their inability to bind and internalize into cells or package incomplete genomes (Fig. 3).”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Upon comparison of the K and L AAV1 transduction profile in the presence of the proteasome inhibitor to that of the nontreated AAV1 E, it is clear that transduction is restored to wt levels for the K vector and to near wt levels for the L vector (less than twofold difference).”
boosted- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“DNA concentrations shown on the alkaline agarose gels and quantitated by dot blots are similar between the AAV2 D through L viruses but do not correlate with the infectivity of each virus.”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Dot blot analysis established that packaging efficiency was similar for all vector cassettes and that the integrity of encapsidated genomes was intact regardless of size.”
boosted- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Titers ranged from 106 to 108 viral genomes/μl for a majority of the viral preparations with little to no differences in titer between AAV produced with the largest cassettes (3 × 106 to 9 × 107 viral genomes/μl) compared to the wt size cassettes (6 × 106 to 1 × 108 viral genomes/μl).”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These data add more support to the previous claim that virions lacking Vp2 do not encapsidate and transduce cells with the larger genomes more efficiently.”
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This study suggests that AAV encapsidating genomes larger than 5.2 kb are not influenced by the presence or absence of Vp2, distinguishing autonomous parvoviruses from AAV.”
hedged- Asserted: passes — The authors put it forward as true.
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- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
In the paper
“Dong et al. generated packaging constructs, containing a completely recombinant genome encoding the chloramphenicol acetyltransferase (CAT) gene, ranging in size from 1,918 to 6,019 bp (10).”
What the sources say
- Not checked — no full text of the sourcecites [10] Dong, J. Y., P. D. Fan, and R. A. Frizzell. 1996. Quantitative analysis of the packaging capacity of recombinant adeno-associated virus. Hum. Gene Ther. 7:2101-2112. [DOI] [PubMed] [Google Scholar] source
plain- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This study illustrates that AAV is capable of packaging and protecting recombinant genomes as large as 6.0 kb but the larger genome-containing virions are preferentially degraded by the proteasome and that this block can be overcome by the addition of proteasome inhibitors.”
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Vectors carrying larger genomes can be enhanced for more efficient transduction by the addition of proteasome inhibitors, suggesting a postentry block.”
hedgedconditional- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Cells have to be infected with numerous virus particles to increase the probability of transduction, and the system is reliant upon the efficiency of homologous recombination.”
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This study suggests that all AAV serotypes are capable of efficiently encapsidating genomes as large as 6 kb regardless of sequence, but the optimum packaging capacity is 5.23 kb.”
hedged- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Based on these studies, it has been proposed that AAV requires endosomal acidification to escape from the late endosome and traffic to the nucleus (Fig. 8III and IV).”
hedgeddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Hermonat et al. inserted increments of 100 bp into the wt AAV genome downstream of the capsid gene (23). Viruses carrying larger genomes (up to 5.6 kb) were able to replicate and produce infectious virions, albeit at reduced efficiency compared to wt.”
What the sources say
- Not checked — no full text of the sourcecites [23] Hermonat, P. L., J. G. Quirk, B. M. Bishop, and L. Han. 1997. The packaging capacity of adeno-associated virus (AAV) and the potential for wild-type-plus AAV gene therapy vectors. FEBS Lett. 407:78-84. [DOI] [PubMed] [Google Scholar] source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Further analysis determined that a postentry step was responsible for the block in infection and specific treatment of cells upon infection with proteasome inhibitors increased transduction of AAV encapsidating larger DNA templates to wt levels, suggesting a preferential degradation of virions encapsidating larger-than-wt genomes.”
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“However, exposure of Vp1 may not be the only factor involved in escape from the endosome, as was indicated in a recent study with CPV (38).”
What the sources say
- Not checked — no full text of the sourcecites [38] Suikkanen, S., M. Antila, A. Jaatinen, M. Vihinen-Ranta, and M. Vuento. 2003. Release of canine parvovirus from endocytic vesicles. Virology 316:267-280. [DOI] [PubMed] [Google Scholar] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The dot blot method is an effective method to quantitate viral titers, but it is incapable of determining whether each AAV serotype has successfully packaged the larger transgene cassettes in their entirety.”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
In the paper
“However, genomes of identical size to wt but possessing sequence foreign to wt showed dissimilar packaging efficiencies, alluding to the importance of primary viral DNA sequence and possibly its structure on packaging into the capsid.”
What the sources say
- Not checked — no full text of the sourcecites [4] Brandenburger, A., E. Coessens, K. El Bakkouri, and T. Velu. 1999. Influence of sequence and size of DNA on packaging efficiency of parvovirus MVM-based vectors. Hum. Gene Ther. 10:1229-1238. [DOI] [PubMed] [Google Scholar] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Infectivity/transduction were restored to wt or near wt levels for AAV encapsidating the 5.3- and 6-kb genomes, respectively, shifting the balance from proteasome degradation to nuclear accumulation, resulting in increased transduction (Fig. 6).”
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“The above studies have found that packaging capacity rarely exceeds 105 to 110% of the size of the wt genome.”
What the sources say
- Not checked — no full text of the sourcecites [2] Bett, A. J., L. Prevec, and F. L. Graham. 1993. Packaging capacity and stability of human adenovirus type 5 vectors. J. Virol. 67:5911-5921. [DOI] [PMC free article] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [3] Bloss, T. A., and B. Sugden. 1994. Optimal lengths for DNAs encapsidated by Epstein-Barr virus. J. Virol. 68:8217-8222. [DOI] [PMC free article] [PubMed] [Google Scholar] source
- Not checked — no full text of the sourcecites [6] Chang, X. B., and J. H. Wilson. 1986. Formation of deletions after initiation of simian virus 40 replication: influence of packaging limit of the capsid. J. Virol. 58:393-401. [DOI] [PMC free article] [PubMed] [Google Scholar] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Subsequent to infection, rAAV can express the therapeutic gene and persist without integration into the host genome by existing episomally in circular head-to-tail concatemers (29).”
What the sources say
- Not checked — no full text of the sourcecites [29] McCarty, D. M., S. M. Young, Jr., and R. J. Samulski. 2004. Integration of adeno-associated virus (AAV) and recombinant AAV vectors. Annu. Rev. Genet. 38:819-845. [DOI] [PubMed] [Google Scholar] source
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The data gathered from these studies provides important information regarding AAV vector design and suggests that AAV packaging limits may not be restricted solely by the physical size of the vector template.”
hedged- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“To control for these inconsistencies, transduction assays were carried out in duplicate with separate viral preparations, and the transduction profiles depicted in Fig. 5 (top and middle panels) were found to hold true for each AAV serotype with and without Vp2.”
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
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Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The two approaches, trans-splicing and homologous recombination methods, depend upon recombination between two vector genomes (each genome encoding approximately half the transgene) within the same cell to achieve gene expression.”
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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Probably not a substantial claim.
The paper relies on this without support.
AAV's limited packaging capacity impedes gene therapy for diseases associated with larger genes.
“The limited packaging capacity of adeno-associated virus (AAV) precludes the design of vectors for the treatment of diseases associated with larger genes.”
“limited packaging capacity has been an impediment for AAV-mediated gene therapy of Duchenne muscular dystrophy, hemophilia A, cystic fibrosis, and other genetic diseases where the length of the coding sequence is equal in size to the wt AAV genome.”
The paper relies on this without support.
Autonomous parvoviruses MVM and B19 package larger genomes of 5.1 and 5.6 kb, respectively, compared to AAV genomes of 4.7 kb.
“Autonomous parvoviruses, such as minute virus of mice and B19, while identical in size (25 nm), are known to package larger genomes of 5.1 and 5.6 kb, respectively, compared to AAV genomes of 4.7 kb.”
“Other parvoviruses have been shown to package genomes as large as 5.1 and 5.6 kb (minute virus of mice [MVM] and B19, respectively).”
The paper relies on this without support.
The functional significance of Vp2 remains unresolved.
“The functional significance of Vp2 remains to be resolved.”
The paper relies on this without support.
MVM and B19 are initially composed of two structural proteins, Vp1 and Vp2, and the N termini of the minor capsid components are exposed on the surface of the virion subsequent to genome encapsidation.
“A striking structural difference is that MVM and B19 are initially composed of two structural proteins (Vp1 and Vp2), and the N termini of the minor capsid components (Vp1 and Vp2 for B19 and Vp2 for MVM) are exposed on the surface of the virion subsequent to genome encapsidation.”
The paper relies on this without support.
Recombinant AAV utilizes cis-acting 145-bp inverted terminal repeats to flank vector transgene cassettes, providing up to 4.5 kb for packaging of foreign DNA.
“Similar to wt AAV, recombinant AAV (rAAV) utilizes the cis-acting 145-bp ITRs to flank vector transgene cassettes, providing up to 4.5 kb for packaging of foreign DNA.”
The paper relies on this without support.
AAV's small size is a major limitation for its use in therapies for diseases associated with larger genes, such as cystic fibrosis.
“However, its small size has been identified as a major limitation for its use in therapies for diseases associated with larger genes, such as cystic fibrosis.”
The paper relies on this without support.
AAV is not dependent on nucleotide-capsid interactions because its genome produces the Vp3 subunit from an independent start codon.
“AAV is not dependent on this mechanism because its genome produces the Vp3 subunit from an independent start codon.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The cited source doesn’t support the claim as written.
In the citing paper
“Although the gene packaging size is limited (maximum 5.0 kb), typically the relevant gene coding sequences can be easily packaged for CNS delivery.”
From AAVrh.10-Mediated APOE2 Central Nervous System Gene Therapy for APOE4-Associated Alzheimer's Disease (2018) · cites this paper as [67]
Checked by a reasoning model — may be wrong.
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Vector reconstitution has been reported in vitro in several cell lines, and in vivo in mouse liver, skeletal muscle, and retina (Grieger and Samulski, 2005).”
From Evaluating Efficiencies of Dual AAV Approaches for Retinal Targeting (2017) · cites this paper as Grieger and Samulski, 2005
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“It has also been shown that vectors carrying larger genomes have lower transduction capacity, most likely due to a preferential degradation of vectors encapsidating larger genomes (Grieger and Samulski, 2005).”
From Evaluating Efficiencies of Dual AAV Approaches for Retinal Targeting (2017) · cites this paper as Grieger and Samulski, 2005
Citations
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Muravyeva, A., & Smirnikhina, S. (2026) · International Journal of Molecular Sciences · doi:10.3390/ijms27062542
AAV vectors for cancer gene therapy
Lee, M., Park, J., Park, J. H., & Curiel, D. T. (2026) · Advances in cancer research · doi:10.1016/bs.acr.2026.02.005
Characterization of rAAV vectors packaging in baculovirusinfected insect cells
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Self-citation
Metadata
- Authors
- Grieger, J. C., & Samulski, R. J.
- Affiliations
- University of North Carolina at Chapel Hill (US)
- Corresponding author
- Samulski, Richard J.
- ORCID
- Samulski, Richard J.
- Venue
- Journal of Virology
- Publisher
- American Society for Microbiology
- Published
- 2005-08
- Volume
- 79
- Issue
- 15
- Pages
- 9933-9944
- ISSN
- 0022-538X (ISSN-L)
- 1098-5514
- PMC
- PMC1181570
- OpenAlex
- W1995793532
- Cited by
- 419
- References
- 57
- Citations by year
- 2026: 22 · 2025: 33 · 2024: 29 · 2023: 24 · 2022: 42 · 2021: 24 · 2020: 31 · 2019: 29 · 2018: 19 · 2017: 22 · 2016: 8 · 2015: 20 · 2014: 11 · 2013: 13 · 2012: 19
- FWCI
- 5.18
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Journal of Virology (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Carolina Digital Repository (University of North Carolina at Chapel Hill) (submittedVersion)
- UNC Libraries
- Funders
- National Institutes of Health (5p01gm059299-10, DK065988)
- National Heart, Lung, and Blood Institute (P01 HL-051818, 5P01HL066973, P01 HL066973, 2P01 HL 051818)
- National Institute of General Medical Sciences (P01 GM-059299, 5P01GM05988)
- National Institute of Diabetes and Digestive and Kidney Diseases (P30DK065988)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Virus-based gene therapy research
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › RNA Interference and Gene Delivery
- Health Sciences › Medicine › Infectious Diseases › Parvovirus B19 Infection Studies
- Keywords
- adeno-associated virus, AAV serotypes, packaging capacity, genome size, transduction efficiency, proteasomal degradation, CFTR gene therapy, adeno-associated virus vectors, minute virus of mice, viral capsid
- MeSH terms
- Dependovirus, Animals, Chlorocebus aethiops, Genetic Vectors, Humans, Gene Expression, Genome, Viral, Gene Deletion, Cystic Fibrosis Transmembrane Conductance Regulator, Virus Assembly, COS Cells, Capsid Proteins
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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
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