Modifications of mRNA vaccine structural elements for improving mRNA stability and translation efficiency

In the paper

“The bulk of the mRNA vaccines reported till date have an m7GpppNm cap inserted at the 5′-end during IVT (Corbett et al. 2020).”

What the sources say

• Partly supported

  The Methods section (Pre-clinical mRNA-1273 mRNA and LNP Production Process; page unavailable) says this vaccine’s mRNA was made by in vitro transcription and received a 5′ Cap 1 structure. It specifies that the cap was added after transcription, not during it, and does not establish what the bulk of reported mRNA vaccines use. (LLM, conf=0.87)

  cites Corbett et al. 2020 sourceExperimental — accuracy not yet measured

In the paper

“The findings revealed that mice administered mRNA-LNP produced protective antibodies, assisting them in overcoming HIV-1 infection (Pardi et al. 2017).”

What the sources say

• Partly supported

  The Results section reports that VRC01 mRNA-LNPs produced antibodies in humanized mice and protected them when administered before HIV-1 challenge. It does not show mice overcoming an established infection. The Methods also specify FPLC purification, not the HPLC purification stated in the supplied paraphrase. (LLM, conf=0.88)

  cites Pardi et al. 2017 sourceExperimental — accuracy not yet measured

In the paper

“For appropriate folding, some proteins require delayed translation, which is guaranteed by uncommon codons (Kimchi-Sarfaty et al. 2007).”

What the sources say

• Partly supported

  The paper’s opening summary (section labeled “1 (”, page unavailable) hypothesizes that a rare codon affects the timing of cotranslational folding of P-glycoprotein. It does not establish that uncommon codons guarantee delayed translation or that some proteins require such a delay for appropriate folding; the citing sentence presents a proposed mechanism as a general fact. (LLM, conf=0.88)

  cites Kimchi-Sarfaty et al. 2007 sourceExperimental — accuracy not yet measured

In the paper

“The modified nucleosides escape the type interferons (IFNs) induced antiviral pathways and are targeted to break and block invading mRNA; therefore they can be used to create mRNA vaccines with significantly improved translation efficiency (Verbeke et al. 2019).”

What the sources say

• Supported

  Section 2.3 states that modified nucleosides allow mRNA vaccines to avoid type I IFN-induced antiviral pathways that degrade or inhibit invading mRNA, thereby improving stability and translation capacity. The source describes the pathways—not the modified nucleosides—as targeting invading mRNA. (LLM, conf=0.95)

  cites Verbeke et al. 2019 source

In the paper

“mRNA transcripts containing modified nucleosides, also known as nucleoside-modified mRNAs, are created with lower immunostimulatory activity and a better safety profile.”

What the sources say

• Supported

  Section 2.3 explicitly says that incorporating modified nucleosides produces transcripts called “nucleoside-modified mRNA” with reduced immunostimulatory activity and, consequently, an improved safety profile. (LLM, conf=0.95)

  cites Verbeke et al. 2019 source

In the paper

“The poly(A) tail steadies mRNA and boosts protein translation, and the length of the poly(A) tail is proportional to translation efficiency.”

What the sources say

• Supported

  The Introduction describes the poly(A) tail as important for mRNA stability and translational regulation, and the Abstract calls poly(A) tails critical for both. This supports the quoted claim. The paper separately limits the relationship between tail length and translation efficiency to short tails; that relationship is not part of the quoted claim. (LLM, conf=0.92)

  cites Park et al. 2016 source
• Supported

  The Introduction says poly(A) tails enhance translation efficiency and that tail shortening is a key step initiating mRNA decay. The section on cytoplasmic factors also describes poly(A)-tail-associated proteins that increase mRNA stability. These passages support the attributed claim; page numbers are not provided in our copy. (LLM, conf=0.91)

  cites Jalkanen et al. 2014 source

In the paper

“The mRNA also does not interact with the genome and only the parts directly required for the encoded protein expression are present in this basic genetic construct (Pardi et al. 2018).”

What the sources say

• Supported

  The Safety section says that integration into host-cell DNA is not a concern for mRNA, supporting the claim about the genome. Basic mRNA vaccine pharmacology describes conventional mRNA constructs as containing the protein-coding sequence, untranslated regions, a 5′ cap and a poly(A) tail; it contrasts these with self-amplifying RNA, which also encodes viral replication machinery. Page numbers are unavailable in our copy. (LLM, conf=0.88)

  cites Pardi et al. 2018 source

In the paper

“mRNA is created via a cell-free enzymatic transcription reaction that enables rapid and scalable production, as illustrated by the current pandemic's rapid pursuit of RNA vaccines (Verbeke et al. 2021).”

What the sources say

• Partly supported

  In “COVID-19 creates momentum for mRNA vaccines” (page unavailable), the paper discusses in vitro-transcribed (IVT) mRNA, and “Conclusions and perspectives” describes exceptionally rapid development and production of COVID-19 mRNA vaccines. It does not explicitly describe a cell-free enzymatic transcription reaction; the scalable production system it identifies is microfluidic mixing to formulate mRNA-loaded nanoparticles, not transcription itself. (LLM, conf=0.82)

  cites Verbeke et al. 2021 sourceExperimental — accuracy not yet measured

In the paper

“They comprise various regulatory regions related to mRNA stability, ribosome recognition, interaction with translational machinery components, and mRNA secondary structures (Tanguay and Gallie 1996).”

What the sources say

• Partly supported

  The introduction describes 3′ UTR elements that regulate mRNA stability and translation, and the Discussion describes interactions with initiation factors and ribosomal machinery. The references identify stem-loops and pseudoknots in untranslated regions, but the paper does not clearly establish the claim about ribosome recognition. Its direct analysis also concerns 3′ UTRs, rather than UTRs generally. (LLM, conf=0.84)

  cites Tanguay and Gallie 1996 sourceExperimental — accuracy not yet measured

In the paper

“The basic structure of mRNA, same as eukaryotic mRNA, is made up of (i) protein encoding ORF, surrounded by (ii) 5′ and 3′ UTRs, and (iii) a 7-methyl guanosine 5′ cap structure and (iv) a 3′poly(A) tail at the end sides (Verbeke et al. 2019; Schlake et al. 2012; Sahin et al. 2014) (Fig. 1).”

What the sources say

• Supported

  Section 2.3 states that IVT mRNA closely resembles mature eukaryotic mRNA and lists the same four structural features: a protein-encoding ORF, flanking 5′ and 3′ UTRs, a 7-methyl guanosine 5′ cap, and a 3′ poly(A) tail. (LLM, conf=0.95)

  cites Verbeke et al. 2019 source
• Supported

  The mRNA Design section describes synthetic mRNA as following the blueprint of eukaryotic mRNA. It identifies a protein-encoding ORF flanked by 5′ and 3′ UTRs, a 7-methyl-guanosine cap at the 5′ end, and a poly(A) tail at the 3′ end. (LLM, conf=0.94)

  cites Schlake et al. 2012 source
• Supported

  The Figure 2 caption identifies the cap, 5′ and 3′ UTRs, ORF, and poly(A) tail as components of the mRNA. The section “The 5′ cap” specifies that natural eukaryotic mRNA has a 7-methylguanosine cap. Together, these passages support the attributed structural description. (LLM, conf=0.94)

  cites Sahin et al. 2014 source

In the paper

“N1-methyl-pseudouridine (1mΨ) nucleotide substitution has been found to increase base pair stability, resulting in complex secondary structure and improved mRNA translation (Mauger et al. 2019).”

What the sources say

• Partly supported

  The Discussion reports that m1Ψ stabilizes base pairing and mRNA secondary structure and generally increases protein output. But the Results section, “Codon Usage and mRNA Structure Synergize to Determine Ribosome Loading and mRNA Half-Life,” finds that protein output correlates poorly with translation rate and strongly with functional mRNA half-life. Thus the structural and protein-output parts are supported, but “improved mRNA translation” overstates the measured mechanism. (LLM, conf=0.86)

  cites Mauger et al. 2019 sourceExperimental — accuracy not yet measured

In the paper

“The 7-methylguanosine (m7G) moiety is found at the 5′ end of natural mRNA in the eukaryotic cytoplasm, followed by a triphosphate connection to the first nucleotide (m7GpppN) (Sahin et al. 2014).”

What the sources say

• Supported

  The “5′ cap” section states that natural eukaryotic mRNA has a 7-methylguanosine cap linked by a 5′–5′ triphosphate bridge, yielding the m7GpppN structure. This supports the attributed description of the cap at the 5′ end. (LLM, conf=0.92)

  cites Sahin et al. 2014 source

In the paper

“The BNT162b2 includes N1-methylpseudouridine, optimized codon; high GC sequence, removed dsRNA, and N1-methylpseudouridine modifications (Polack et al. 2020).”

What the sources say

• Partly supported

  The Abstract Methods identifies BNT162b2 as a nucleoside-modified RNA vaccine, supporting the general modification claim. Our copy does not specify N1-methylpseudouridine, codon optimization, high GC content, or removal of double-stranded RNA; searches for those terms found no supporting passage. Page numbers were not available in our copy. (LLM, conf=0.88)

  cites Polack et al. 2020 sourceExperimental — accuracy not yet measured

In the paper

“The COVID-19 vaccine candidates demonstrate the structurally modified mRNA approach allows for higher tolerated doses and may be more suitable for producing a fast antibody response (Verbeke et al. 2021).”

What the sources say

• Supported

  The Conclusions and perspectives section says the COVID-19 case suggests that nucleoside-modified mRNA permits higher maximal tolerable doses and might be better suited to rapidly generating antibody responses. It cautions that direct comparisons between vaccine candidates require care; the citing sentence preserves the uncertainty about antibody responses. (LLM, conf=0.90)

  cites Verbeke et al. 2021 source

In the paper

“In addition, 5′ UTR: human -globin RNA with optimized Kozak sequence, 3′ UTR: AES and mtRNR1 3′ UTR Motives, and 110 Poly(A) tail with nucleotide-linker (GCAUAUGACU) are also used (Orlandini von Niessen et al. 2019).”

What the sources say

• Partly supported

  The Results (page unavailable) describe AES and mtRNR1 motifs combined in experimental mRNA 3′ UTRs, supporting that component of the description. The paper does not identify BNT162b2 or establish its 5′ UTR, optimized Kozak sequence, or specified 110-adenosine tail and linker. Its Results instead describe a reporter with a 60-adenosine tail, which does not determine BNT162b2’s composition. (LLM, conf=0.87)

  cites Orlandini von Niessen et al. 2019 sourceExperimental — accuracy not yet measured

In the paper

“The technique can be easily scaled requiring minimum platform changes during mRNA formulation and production (Pardi et al. 2018).”

What the sources say

• Partly supported

  The Good manufacturing practice production section (page not provided) describes mRNA manufacturing as sequence-independent and largely standardized, supporting scalability with limited production-process changes. It does not establish that formulation likewise requires minimal platform changes; it describes pharmaceutical formulation as an active area of development. (LLM, conf=0.84)

  cites Pardi et al. 2018 sourceExperimental — accuracy not yet measured

In the paper

“Moderna on the other hand used N1-methylpseudouridine, removed dsRNA, and undisclosed structural elements (Baden et al. 2021) (Fig. 2A).”

What the sources say

• ?Could not verify

  The Background (p. 1) describes mRNA-1273 as an mRNA vaccine encoding a stabilized spike protein, but does not specify its nucleoside modifications or manufacturing steps. Searches for N1-methylpseudouridine, dsRNA removal, and structural elements found no passage in our copy addressing those claims. (LLM, conf=0.73)

  cites Baden et al. 2021 sourceExperimental — accuracy not yet measured

In the paper

“The extraction of neutralizing antibodies from COVID-19 patient’s serum verified the S protein’s high immunogenicity, whereas the receptor binding domain (RBD) and N-terminal domains were also equally immunogenic (NTD).”

What the sources say

• Partly supported

  The opening summary (p. 1) reports neutralizing antibodies from five COVID-19 patients and says the potent antibodies were about equally divided between RBD and NTD targets, indicating that both spike regions are immunogenic. But “Isolation and construction of mAbs” (p. 2) describes sorting spike-binding memory B cells from blood and producing monoclonal antibodies from their sequences, not extracting antibodies from patient serum. (LLM, conf=0.90)

  cites Liu et al. 2020 sourceExperimental — accuracy not yet measured

In the paper

“Protein-based vaccinations are usually made from bacteria, however mRNA vaccines can be produced by the host translation machinery, resulting in an antigen that closely resembles the structure of the protein released from the viral genome (Park et al. 2021).”

What the sources say

• Supported

  The section “Advantages and disadvantages of mRNA vaccines over other vaccine platforms” directly states that protein-based vaccines are often produced from bacteria, while mRNA vaccines use host translation machinery to form an antigen likely to mimic the structure of the protein expressed from the viral genome. The citing sentence preserves that qualified comparison. (LLM, conf=0.94)

  cites Park et al. 2021 source

In the paper

“Poly(A) tails of approximately 100 nt are ideal for synthesizing mRNA therapies because tail size affects mRNA decay by modulating 3′ exonucleolytic degradation (Schlake et al. 2012).”

What the sources say

• Partly supported

  The Poly(A) tail section reports that tail length affects protein expression, but its results vary by cell type and do not establish approximately 100 nucleotides as ideal. The mRNA Design section says poly(A) tails help stabilize mRNA where decay is predominantly catalyzed by exonucleases; it does not say tail size modulates 3′ exonucleolytic degradation. Page numbers were unavailable in our copy. (LLM, conf=0.86)

  cites Schlake et al. 2012 sourceExperimental — accuracy not yet measured

In the paper

“IVT is a low-cost method of mRNA synthesis; however the immunogenicity of mRNA is the most challenging obstacle it faces (Sahin et al. 2014).”

What the sources say

• Supported

  The Conclusions and perspectives section states that IVT mRNA can be manufactured at relatively low cost. The Principal concept of mRNA pharmacology section explains that the mRNA is synthesized by in vitro transcription, supporting the claim that IVT is a low-cost synthesis method. (LLM, conf=0.94)

  cites Sahin et al. 2014 source

In the paper

“The basic concept underlying mRNA vaccines is to encode the antigen in mRNA and transfer the transcript to the host cell’s cytoplasm via a non-viral delivery route, permitting antigen expression and stimulation of an antigen-specific immune response (Jackson et al. 2020).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Jackson et al. 2020

In the paper

“Destabilizing mRNA may be useful in some applications to reduce the time required for protein synthesis.”

In the paper

“5′-UTR regulatory elements and the length of the 3′-UTR aid translation of protein.”

In the paper

“5-methylcytidine (m5C) and pseudouridine (ψ) nucleotide modifications are commonly preferred in base-pair alterations as they lower immunogenicity while increasing the efficiency of translation (Weng 2020).”

What the sources say

• ?Not checked — no full text of the sourcecites Weng 2020 source

In the paper

“The 5′ cap regulates pre-mRNA splicing and nuclear export, works as a protective structure that shields RNA from exonuclease cleavage, and initiates mRNA translation.”

In the paper

“Unmodified mRNA, on the other hand, showed no significant alterations and merely elicited a considerable immunological response (Kormann et al. 2011).”

What the sources say

• ?Not checked — no full text of the sourcecites Kormann et al. 2011 source

In the paper

“The translation and stability of mRNA can be improved and critical tasks have been undertaken to identify desirable mRNA elements.”

In the paper

“ARCA-capped mRNA has been shown to boost and extend protein expression in cultured cells (Zohra et al. 2007).”

What the sources say

• ?Not checked — no full text of the sourcecites Zohra et al. 2007 source

In the paper

“Translation efficiency, mRNA abundance, and protein folding may all be affected by codon optimization.”

In the paper

“These components can be modified or altered to increase the stability, translation efficiency, and immune-stimulatory feature of mRNA (Table 1).”

In the paper

“The start codon should include Kozak sequence (Kozak 1986), and the stop codon's sequence can be modified (Liu 2005).”

What the sources say

• ?Not checked — no full text of the sourcecites Kozak 1986 source

In the paper

“Optimizing the mRNA structural features particularly the 5′ cap, 5′ and 3′UTRs, the coding region, and the poly(A) tail increases the mRNA’s control of immune responses resulting in higher translational efficiency.”

In the paper

“The efficacy of both the mRNA vaccines is more than 90% (~ 95% to be precise).”

In the paper

“Modifying or improving the structural features can boost the mRNA’s potential to control innate immune responses, resulting in increased translation capacity and bioavailability.”

In the paper

“Despite the advantages of mRNA vaccines there are still many risks involved such as long term effects of the mRNA vaccine are unknown.”

In the paper

“mRNA vaccines provide flexibility in development as any protein can be made from mRNA without changing the production or application procedure.”

In the paper

“Spike proteins with K986P, V987P substitutions are common in both vaccines.”

In the paper

“The final result can be dramatically improved by optimizing the structure of mRNA.”

In the paper

“Enzymatic polyadenylation has the disadvantage of having a variety of RNA species with variable poly(A) tail lengths in each RNA preparation.”

In the paper

“Furthermore, mRNA is a transient molecule carries a short translation sequence it has no interaction with the host genome.”

In the paper

“Vaccine development often requires years of research and testing to ensure efficacy and safety.”

In the paper

“HPLC, anion exchange and affinity chromatography, are used in the purification process to remove truncated transcripts (Weissman et al. 2013).”

What the sources say

• ?Not checked — no full text of the sourcecites Weissman et al. 2013 source

In the paper

“The COVID-19 pandemic has increased the interest in mRNA vaccinations.”

In the paper

“mRNA vaccines work on the principle of delivering a transcript that encodes a target antigen or immunogen.”

In the paper

“Contrarily, in vitro transcription (IVT) of RNA from a DNA template produces RNA with a predetermined poly(A) tail length, which is preferable, particularly for clinical purposes.”

In the paper

“Because antigen translation occurs in the cytoplasm rather than the nucleus; therefore mRNA vaccines have a greater biosafety than DNA vaccines as their antigens are translated into the cytoplasm rather than the nucleus, making it more difficult for the mRNA to integrate into the genome.”

In the paper

“Adding poly(A) tails lowers mRNA immunogenicity by lowering U content and shielding mRNA in the sequence.”

In the paper

“Because of the ease and speed with which mRNA vaccines may be produced, they are often favored over alternative platforms.”

In the paper

“In contrast, the two mRNA vaccines took less than a year to develop and deploy from start to finish.”

In the paper

“Their rapid creation, manufacture, and excellent effectiveness in preventing SARS-CoV-2 infection, show that mRNA-based therapies are ready for application in the future.”

In the paper

“After transfection, mRNA vaccine expresses the protein target (antigen) via translation from mRNA.”