title: Dynamic FtsA and FtsZ localization and outer membrane alterations during polar growth and cell division in Agrobacterium tumefaciens.
abstract: Growth and cell division in rod-shaped bacteria have been primarily studied in species that grow predominantly by peptidoglycan (PG) synthesis along the length of the cell. Rhizobiales species, however, predominantly grow by PG synthesis at a single pole. Here we characterize the dynamic localization of several Agrobacterium tumefaciens components during the cell cycle. First, the lipophilic dye FM 4-64 predominantly stains the outer membranes of old poles versus growing poles. In cells about to divide, however, both poles are equally labeled with FM 4-64, but the constriction site is not. Second, the cell-division protein FtsA alternates from unipolar foci in the shortest cells to unipolar and midcell localization in cells of intermediate length, to strictly midcell localization in the longest cells undergoing septation. Third, the cell division protein FtsZ localizes in a cell-cycle pattern similar to, but more complex than, FtsA. Finally, because PG synthesis is spatially and temporally regulated during the cell cycle, we treated cells with sublethal concentrations of carbenicillin (Cb) to assess the role of penicillin-binding proteins in growth and cell division. Cb-treated cells formed midcell circumferential bulges, suggesting that interrupted PG synthesis destabilizes the septum. Midcell bulges contained bands or foci of FtsA-GFP and FtsZ-GFP and no FM 4-64 label, as in untreated cells. There were no abnormal morphologies at the growth poles in Cb-treated cells, suggesting unipolar growth uses Cb-insensitive PG synthesis enzymes.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Zupan
authors.forename: Todd A
authors.initials: TA
authors.lastname: Cameron
authors.forename: James
authors.initials: J
authors.lastname: Anderson-Furgeson
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Zambryski
mesh_terms: D016960:Agrobacterium tumefaciens / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D002228:Carbenicillin; D002455:Cell Division / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D003001:Cloning, Molecular; D019295:Computational Biology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000096:biosynthesis; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; C092350:FM 4-64; C065103:FtsA protein, Bacteria; C071525:FtsZ protein, Bacteria; D010457:Peptidoglycan; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D049452:Green Fluorescent Proteins; D002228:Carbenicillin
keywords: agrobacterium cell cycle; bacterial cell division; bacterial cell growth; peptidoglycan synthesis