title: Interference of Mycobacterium tuberculosis cell division by Rv2719c, a cell wall hydrolase.
abstract: The genetic factors responsible for the regulation of cell division in Mycobacterium tuberculosis are largely unknown. We showed that exposure of M. tuberculosis to DNA damaging agents, or to cephalexin, or growth of M. tuberculosis in macrophages increased cell length and sharply elevated the expression of Rv2719c, a LexA-controlled gene. Overexpression of Rv2719c in the absence of DNA damage or of antibiotic treatment also led to filamentation and reduction in viability both in broth and in macrophages indicating a correlation between Rv2719c levels and cell division. Overproduction of Rv2719c compromised midcell localization of FtsZ rings, but had no effect on the intracellular levels of FtsZ. In vitro, the Rv2719c protein did not interfere with the GTP-dependent polymerization activity of FtsZ indicating that the effects of Rv2719c on Z-ring assembly are indirect. Rv2719c protein exhibited mycobacterial murein hydrolase activity that was localized to the N-terminal 110 amino acids. Visualization of nascent peptidoglycan (PG) synthesis zones by probing with fluoresceinated vancomycin (Van-FL) and localization of green fluorescent protein-Rv2719c fusion suggested that the Rv2719c activity is targeted to potential PG synthesis zones. We propose that Rv2719c is a potential regulator of M. tuberculosis cell division and that its levels, and possibly activities, are modulated under a variety of growth conditions including growth in vivo and during DNA damage, so that the assembly of FtsZ-rings, and therefore the cell division, can proceed in a regulated manner.
authors.affiliation: Biomedical Research, The University of Texas Health Center at Tyler, 11937 US Hwy 271, Tyler, TX 75708-3154, USA.
authors.forename: Ashwini
authors.initials: A
authors.lastname: Chauhan
authors.forename: Hava
authors.initials: H
authors.lastname: Lofton
authors.forename: Erin
authors.initials: E
authors.lastname: Maloney
authors.forename: Jacob
authors.initials: J
authors.lastname: Moore
authors.forename: Marek
authors.initials: M
authors.lastname: Fol
authors.forename: Murty V V S
authors.initials: MV
authors.lastname: Madiraju
authors.forename: Malini
authors.initials: M
authors.lastname: Rajagopalan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival; D002473:Cell Wall / Q000378:metabolism*; D002478:Cells, Cultured; D002506:Cephalexin / Q000494:pharmacology; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis / Q000187:drug effects; D015151:Immunoblotting; D008264:Macrophages / Q000166:cytology / Q000382:microbiology; D008856:Microscopy, Fluorescence; D009154:Mutation / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D006867:Hydrolases; D009238:N-Acetylmuramoyl-L-alanine Amidase; D002506:Cephalexin