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Cited by 29Bacterial Genetics and BiotechnologyTuberculosis Research and EpidemiologyMicrotubule and mitosis dynamics

ChiZ levels modulate cell division process in mycobacteria

Open access
Vadrevu, Indumathi S., Lofton, Hava, Sarva, Krishna, Blasczyk, Ewelina, Plocinska, Renata, Chinnaswamy, Jagannath, Madiraju, Murty, Rajagopalan, Malini·2011·Tuberculosis
DOI 10.1016/j.tube.2011.10.022PMC PMC3256928
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Abstract

SUMMARY We have previously shown that expression of chiZ (Rv2719c), encoding a cell wall hydrolase, is upregulated in response to DNA damaging agents and exposure to cephalexin. Furthermore, increased levels of ChiZ lead to decreased viability, loss of membrane integrity and defects in FtsZ-GFP localization and cell division. We now show that ChiZ N′-terminal 110 amino acid region, containing the cell wall hydrolase activity, is sufficient to modulate FtsZ-GFP localization. Further, we found that FtsZ-GFP rings are stabilized in a chiZ deletion strain indicating that ChiZ activity regulates FtsZ assembly. Over-expression of ftsZ did not reverse the reduction in viability caused by overproduction of ChiZ indicating that ChiZ neither interacts with nor directly influences FtsZ assembly. Bacterial two-hybrid assays revealed that ChiZ interacts with FtsI and FtsQ, two other septasomal proteins, but not with FtsZ. Finally, we show that ChiZ is not required for virulence of Mycobacterium tuberculosis in murine macrophages and mice. Our data suggest that optimal levels and activity of the cell wall hydrolase ChiZ are required for regulated cell division in mycobacteria.

Integrity signals

Registry

Crossref · 10.1016/j.tube.2011.10.022

Cites

36 of 36 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

15 of 16 cited sources checked · 10 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Without ChiZ, the cell division defect becomes worse during growth inside macrophages.

    “Since chiZ expression is downregulated during hypoxia and ChiZ loss leads to an enhanced cell division defect during intra-macrophage growth,15 we speculate that ChiZ activity is dispensable during persistent growth, but could be important for recovery of growth from the persistent phase.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source

      The Results (page unavailable) report that the Rv2719c-deletion strain grew similarly to wild type inside macrophages and showed less filamentation, not a worsened cell-division defect. Its cell length increased by 9%, compared with about 47% for wild type and the complemented strain. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Interpretationown data

    ChiZ function controls how FtsZ assembles.

    “Further, we found that FtsZ-GFP rings are stabilized in a chiZ deletion strain indicating that ChiZ activity regulates FtsZ assembly.”
    • Also stated in: § 3.6. ChiZ is not required for virulence of M. tuberculosis in vivo · plain
      “We showed that ChiZ is induced upon DNA damage and during intra-macrophage growth; and modulates FtsZ-ring assembly.15”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source
  • Premisecitation

    In vitro, isolated ChiZ fails to inhibit FtsZ assembly.

    “These studies also showed that ChiZ overproduction led to destabilization of FtsZ-rings in vivo, but that purified ChiZ did not interfere with FtsZ assembly in vitro.15”
    • Also stated in: § 3.3. Overproduction of FtsZ does not reverse the cell viability defect associated with the elevated levels of ChiZ · plain
      “Although overproduction of ChiZ interfers with midcell FtsZ assembly and decreases the viability, purified ChiZ protein did not inhibit in vitro GTP induced FtsZ assembly15 implying that ChiZ does not have a direct effect on FtsZ assembly.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source
  • Premisecitation

    In M. smegmatis, a ChiZ-GFP fusion is found at the midcell and at cell poles, where nascent peptidoglycan is made.

    “We showed that ChiZ-GFP localizes to sites of nascent PG synthesis, viz. midcell and cell poles.15”
    • Also stated in: § 3.4. ChiZ interacts with FtsI and FtsQ · plain
      “We have previously shown that a GFP-ChiZ fusion protein localizes to midcell sites and poles in M. smegmatis.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source
  • Premisecitation

    Excess ChiZ destabilizes FtsZ rings inside cells.

    “These studies also showed that ChiZ overproduction led to destabilization of FtsZ-rings in vivo, but that purified ChiZ did not interfere with FtsZ assembly in vitro.15”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source

      The Results report that Rv2719c overproduction reduced FtsZ-ring numbers by 60% in cells and compromised ring formation; purified Rv2719c did not affect FtsZ polymerization in vitro. Our copy does not identify Rv2719c as ChiZ (searched: ChiZ), so the claim’s naming of the protein cannot be verified from this source alone. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
  • May combine two claims. 12
  • Classified as probably not a substantial claim. 3
  • The quote only partly states this claim. 1

  • May combine two claims.

    Premisecitation

    ChiZ (Rv2719c) functions as a cell wall hydrolase, and its expression increases after treatment with DNA-damaging agents or cephalexin.

    “We have previously shown that expression of chiZ (Rv2719c), encoding a cell wall hydrolase, is upregulated in response to DNA damaging agents and exposure to cephalexin.”
    • Also stated in: § 1. Introduction · plain
      “Our previous studies characterized ChiZ, a small membrane protein, as a cell wall hydrolase that is induced upon DNA damage and intra-macrophage growth and interferes with cell division.15”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source

  • May combine two claims.

    Premiseown data

    Higher amounts of ChiZ result in lower viability, compromised membrane integrity, and abnormal FtsZ-GFP localization and cell division.

    “Furthermore, increased levels of ChiZ lead to decreased viability, loss of membrane integrity and defects in FtsZ-GFP localization and cell division.”
    • Also stated in: § 1. Introduction · plain
      “Our previous studies characterized ChiZ, a small membrane protein, as a cell wall hydrolase that is induced upon DNA damage and intra-macrophage growth and interferes with cell division.15”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source

      The Results (page not available in our copy) report reduced growth and viability, increased membrane permeability, and defective cell division when Rv2719c is overproduced. They also report abnormal FtsZ-YFP structures, not FtsZ-GFP localization. Our copy does not identify Rv2719c as ChiZ, so it does not establish that the named protein is the same. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    During intracellular growth, M. tuberculosis encounters reactive oxygen and nitrogen species.

    “Since M. tuberculosis is exposed to reactive oxygen and nitrogen species during intracellular growth,31,32 we considered a possibility that ChiZ activity might contribute to optimal M. tuberculosis survival upon infection.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [31] Rosenberger, 2002, Macrophages inhibit Salmonella typhimurium replication through MEK/ERK kinase and phagocyte NADPH oxidase activities, J Biological Chemistry source

      The Discussion (page unavailable) describes oxidative and nitrosative stresses on intracellular Salmonella, and mentions phagocyte oxidase responses following M. tuberculosis infection. It does not establish that M. tuberculosis encounters both reactive oxygen and nitrogen species during intracellular growth; the paper’s direct evidence concerns Salmonella. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [32] Woodmansee, 2003, Kinetics of the initial rounds of cell division of Toxoplasma gondii, J Parasitol source

  • Classified as probably not a substantial claim.

    Premisecitation

    Removing several cell wall hydrolases in E. coli barely changes cell shape or division.

    “It is known that bacteria contain multiple cell wall hydrolases and deletion of multiple hydrolases in E. coli has minimal effect on cell morphology and cell division.35”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [35] Heidrich, 2002, Effects of multiple deletions of murein hydrolases on viability, septum cleavage, and sensitivity to large toxic molecules in Escherichia coli, J Bacteriol source

      The Discussion reports that a mutant lacking seven hydrolases grew without an obvious overall phenotypic change. But the Results report that most mutants had severely impaired septum cleavage, forming chains of cells, and that some also changed shape. Thus the claim overstates how little the deletions affected morphology and division-related cell separation. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    ChiZ production increases after DNA damage and during growth inside macrophages.

    “We showed that ChiZ is induced upon DNA damage and during intra-macrophage growth; and modulates FtsZ-ring assembly.15”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Chauhan, 2006, Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase, Mol Microbiol source

  • Classified as probably not a substantial claim.

    Premisecitation

    Higher FtsZ amounts have been reported to block cell division and lower viability in M. smegmatis and M. tuberculosis.

    “Increased levels of FtsZ have previously been shown to inhibit cell division and decrease cell viability of M. smegmatis and M. tuberculosis, presumably due to sequestration of cell division proteins and/or formation of non-productive FtsZ structures.26”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [26] Dziadek, 2002, Physiological consequences associated with overproduction of Mycobacterium tuberculosis FtsZ in mycobacterial hosts, Microbiology source

  • May combine two claims.

    Findingown data

    When ChiZsmegΔLysM is overexpressed in the M. smegmatis Pami-ftsZ-yfp strain, cells become filamentous and show abnormal FtsZ ring assembly.

    “These cells were filamentous and showed defects in FtsZ ring assembly (Figure 1B, compare panels ii and iv; Table 1), as with the full-length protein.15”
    Quote in the paperSubstantial claim
    • Rests on an assumption: FtsZ-GFP and FtsZ-YFP fusion proteins behave like native FtsZ in assembly and localization.

  • May combine two claims.

    Findingown data

    Overexpressing ChiZsmegΔLysM lowers the proportion of midcell FtsZ-GFP rings to 6% from 33% in wild type and raises aberrantly localized FtsZ-GFP structures to 22% from 1.5% in wild type.

    “Overexpression of PdnaA‷chiZsmegΔLysM led to a decrease in the number of midcell FtsZ-GFP rings (6% vs WT = 33%) and an increase in the number of aberrantly localized FtsZ-GFP structures (22% vs WT 1.5%).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: FtsZ-GFP and FtsZ-YFP fusion proteins behave like native FtsZ in assembly and localization.

  • May combine two claims.

    Findingown data

    FtsZ-GFP rings could be seen in M. tuberculosis ΔchiZ without adding anhydrotetracycline, but the wild-type strain needed the inducer.

    “Furthermore, addition of the inducer anhydrotetracycline was not required for visualization of FtsZ-GFP rings in the ΔchiZ strain whereas anhydrotetracycline was required for visualization of FtsZ-GFP rings in wild type strain (Figure 2, compare panels ii and iv).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Producing extra C-terminal LysM domain or extra TMH plus C-terminal regions had no effect on cell division or FtsZ assembly.

    “Merodiploids over-producing either C′-term LysM domain (pACR9 in Table 1) or TMH + C′-term regions (pLR55 in Table 1) did not affect cell division and FtsZ assembly (data not shown).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In M. tuberculosis ΔchiZ, FtsZ-GFP rings appear brighter and fade more slowly than in the control strain.

    “The FtsZ rings in this strain were more vibrant and tended to bleach slower as compared to the corresponding control strain indicating that the FtsZ-GFP rings are stable in the the absence of ChiZ (Figure 2).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The rate at which FtsZ-GFP fluorescence fades is a valid indicator of FtsZ ring stability.

  • May combine two claims.

    Findingown data

    The M. smegmatis ΔchiZ strain had about 24% longer cells than wild type, with no change in the count of FtsZ-YFP rings.

    “Compared to the wild type strain, a modest 24% increase in cell length but no change in the number of FtsZ-YFP rings was noted in the M. smegmatis ΔchiZ strain.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: FtsZ-GFP and FtsZ-YFP fusion proteins behave like native FtsZ in assembly and localization.

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    Bacterial two-hybrid tests show ChiZ binding to FtsI and FtsQ, but not to FtsZ, FtsW, or Wag31.

    “Bacterial two-hybrid assays revealed that ChiZ interacts with FtsI and FtsQ, two other septasomal proteins, but not with FtsZ.”
    • Also stated in: § 3.4. ChiZ interacts with FtsI and FtsQ · hedged
      “Our data indicated that ChiZ interacted with FtsI, an essential transpeptidase belonging to the class B penicillin binding protein family, but not with FtsZ and Wag31 (Figure 4).”
    • Also stated in: § 3.4. ChiZ interacts with FtsI and FtsQ · plain
      “We also found that ChiZ did not interact with FtsW (data not shown).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Positive signals in the bacterial two-hybrid assay reflect direct physical interactions between the tested proteins in vivo.

  • May combine two claims.

    Interpretationown data

    M. tuberculosis does not need ChiZ to be virulent in murine macrophages or mice.

    “Finally, we show that ChiZ is not required for virulence of Mycobacterium tuberculosis in murine macrophages and mice.”
    • Also stated in: § 3.6. ChiZ is not required for virulence of M. tuberculosis in vivo · hedged
      “These data indicated that loss of chiZ had no effect on the growth of M. tuberculosis in mice lungs and spleen.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    ChiZ may aid cell wall hydrolysis during septum formation and help direct FtsZ assembly to the midcell.

    “Nonetheless, results shown in this study tend to suggest that ChiZ activities could contribute to cell wall hydrolysis during septum formation and to help focus the FtsZ assembly to the midcell sites.”
    Quote in the paperSubstantial claim
15 of 15

  • The paper relies on this without support.

    The rate at which FtsZ-GFP fluorescence fades is a valid indicator of FtsZ ring stability.

    “The FtsZ rings in this strain were more vibrant and tended to bleach slower as compared to the corresponding control strain indicating that the FtsZ-GFP rings are stable in the the absence of ChiZ (Figure 2).”

  • The paper relies on this without support.

    Positive signals in the bacterial two-hybrid assay reflect direct physical interactions between the tested proteins in vivo.

    “Our data indicated that ChiZ interacted with FtsI, an essential transpeptidase belonging to the class B penicillin binding protein family, but not with FtsZ and Wag31 (Figure 4).”

  • The paper relies on this without support.

    The cell wall hydrolase activity in the N-terminal 110 amino acid region of ChiZ is responsible for its effects on FtsZ localization and cell division.

    “We now show that ChiZ N′-terminal 110 amino acid region, containing the cell wall hydrolase activity, is sufficient to modulate FtsZ-GFP localization.”

  • The paper relies on this without support.

    FtsZ-GFP and FtsZ-YFP fusion proteins behave like native FtsZ in assembly and localization.

    “To ascertain that the filamentation is due to disruption of FtsZ-ring assembly, we expressed PdnaA‷chiZsmegΔLysM (pLR54, Table 1) in M. smegmatis Pami‷ftsZ-yfp strain and examined the FtsZ assembly in exponential cultures.”

  • The paper relies on this without support.

    GFP-FtsQ, GFP-FtsI, and Wag31-mCherry fusion proteins localize like their native counterparts.

    “Absence of ChiZ had no significant effect on the localization of GFP-FtsQ, GFP-FtsI and Wag31-mCherry (Figure 5) indicating that ChiZ is not required for localization of FtsI, FtsQ and Wag31 proteins.”
5 of 5

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • The same localization experiment labels FtsZ as both YFP and GFP

    Minor

    The described strain expresses an FtsZ-YFP fusion, but the reported ring and localization counts are labeled FtsZ-GFP.

  • Macrophage samples are assigned two different plating media

    Minor

    The methods say macrophage lysates were plated on Middlebrook 7H10, while the results say the same three-day infection samples were plated on Middlebrook 7H11.

2 of 2

Cited works that were retracted

Works this paper cites that were later retracted, from the retraction notices publishers deposit. Major when the notice came out before this paper was published.

  • Cites a retracted work: 10.1371/journal.pone.0008590

    Info

    The cited work was retracted on 2022-02-24 (notice 10.1371/journal.pone.0264672), not before this paper was published (2011-12).

    Cited work 10.1371/journal.pone.0008590 · retracted 2022-02-24 · notice 10.1371/journal.pone.0264672 · this paper published 2011-12

1 of 1

Cites

1 retracted

Flagged first, then by citations

Research works printed but not linked: 1

  1. Gupta, 2010, The Mycobacterium tuberculosis protein LdtMt2 is a nonclassical transpeptidase required for virulence and resistance to amoxicillin, Nat Medicine, 16, 466, 10.1038/nm.2120 · DOI · Paper page

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Authors
Vadrevu, I. S., Lofton, H., Sarva, K., Blasczyk, E., Plocinska, R., Chinnaswamy, J., Madiraju, M., & Rajagopalan, M.
Affiliations
  • The University of Texas Health Science Center at Tyler (US)
  • The University of Texas at Tyler (US)
Corresponding author
Rajagopalan, Malini
Venue
Tuberculosis
Publisher
Elsevier BV
Published
2011-12
Volume
91
Pages
S128-S135
ISSN
1472-9792 (ISSN-L)
DOI
10.1016/j.tube.2011.10.022
PMC
PMC3256928
OpenAlex
W1970777163
Semantic Scholar
252631e96988fb5e49d096b3c446fde7b18a7604
Cited by
28
References
36
Citations by year
2026: 5 · 2021: 1 · 2020: 4 · 2019: 4 · 2018: 1 · 2017: 2 · 2015: 3 · 2014: 2 · 2013: 3 · 2012: 2
FWCI
1.59
Type
journal article
Language
en
Open access
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations
  • Tuberculosis (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute of Allergy and Infectious Diseases (R01AI084734, R01AI049534, R01AI048417)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Bacterial Genetics and Biotechnology
  • Health Sciences › Medicine › Infectious Diseases › Tuberculosis Research and Epidemiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Microtubule and mitosis dynamics
Keywords
cell wall hydrolases, bacterial cell division, Mycobacterium tuberculosis, FtsI, FtsQ, DNA damage response, cephalexin, membrane integrity
MeSH terms
Animals, Bacterial Proteins, Cell Division, Cell Line, Cytoskeletal Proteins, Female, Hydrolases, Macrophages, Membrane Proteins, Mice, Inbred C57BL, Microscopy, Fluorescence, Mycobacterium Infections, Mycobacterium tuberculosis, Virulence, Gene Expression Regulation, Bacterial, Mycobacterium smegmatis, Two-Hybrid System Techniques, Mice

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