The goal of this proposal is to identify the mechanisms of DNA segregation for large, low copy number plasmids in Bacillus species. From studying plasmid pBtoxis in Bacillus thuringiensis, we identified a novel segregation protein belonging to the tubulin superfamily. TubZ is a divergent tubulin like protein that assembles dynamic polymers essential for the stable inheritance of plasmid pBtoxis. Tubulin-like proteins are commonly found on Bacillus virulence plasmids, but how they contribute to plasmid stability is unknown. We have also identified several families of divergent actin-like proteins involved in plasmid DNA segregation in Bacillus subtilis. AlfA of plasmid pLS32 and Alp7A both assemble polymers, but they appear to segregate plasmids by different mechanisms. The goal of this proposal is to understand the biochemical properties, in vivo assembly dynamics, and the functions of Bacillus tubulins and actins involved in plasmid DNA segregation. Since a wide variety of virulence factors are encoded on plasmids in pathogenic strains of Bacillus, such as pXO1 of B. anthracis, understanding how plasmids are transmitted from one generation to the next is important for understanding the evolution and spread of these key virulence determinants.

Public Health Relevance

This study focuses on understanding how bacterial plasmids are inherited. Plasmids play key roles in bacterial pathogenesis, as they are often transmissible and encode antibiotic resistance and virulence traits, such as toxins and capsules. These studies could therefore help identify targets for new narrow spectrum antibiotics, since blocking plasmid stability will in certain infections decrease pathogenicity.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM073898-07
Application #
8310033
Study Section
Special Emphasis Panel (ZRG1-GGG-F (02))
Program Officer
Deatherage, James F
Project Start
2006-08-01
Project End
2014-07-31
Budget Start
2012-08-01
Budget End
2013-07-31
Support Year
7
Fiscal Year
2012
Total Cost
$322,196
Indirect Cost
$109,346
Name
University of California San Diego
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Sakoulas, George; Rose, Warren; Nonejuie, Poochit et al. (2014) Ceftaroline restores daptomycin activity against daptomycin-nonsusceptible vancomycin-resistant Enterococcus faecium. Antimicrob Agents Chemother 58:1494-500
Sakoulas, George; Okumura, Cheryl Y; Thienphrapa, Wdee et al. (2014) Nafcillin enhances innate immune-mediated killing of methicillin-resistant Staphylococcus aureus. J Mol Med (Berl) 92:139-49
Parent, Kristin N; Erb, Marcella L; Cardone, Giovanni et al. (2014) OmpA and OmpC are critical host factors for bacteriophage Sf6 entry in Shigella. Mol Microbiol 92:47-60
Erb, Marcella L; Kraemer, James A; Coker, Joanna K C et al. (2014) A bacteriophage tubulin harnesses dynamic instability to center DNA in infected cells. Elife 3:
Nonejuie, Poochit; Burkart, Michael; Pogliano, Kit et al. (2013) Bacterial cytological profiling rapidly identifies the cellular pathways targeted by antibacterial molecules. Proc Natl Acad Sci U S A 110:16169-74
Barr, Jeremy J; Auro, Rita; Furlan, Mike et al. (2013) Bacteriophage adhering to mucus provide a non-host-derived immunity. Proc Natl Acad Sci U S A 110:10771-6
Werth, B J; Vidaillac, C; Murray, K P et al. (2013) Novel combinations of vancomycin plus ceftaroline or oxacillin against methicillin-resistant vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA. Antimicrob Agents Chemother 57:2376-9
Sakoulas, George; Bayer, Arnold S; Pogliano, Joseph et al. (2012) Ampicillin enhances daptomycin- and cationic host defense peptide-mediated killing of ampicillin- and vancomycin-resistant Enterococcus faecium. Antimicrob Agents Chemother 56:838-44
Derman, Alan I; Nonejuie, Poochit; Michel, Brittany C et al. (2012) Alp7R regulates expression of the actin-like protein Alp7A in Bacillus subtilis. J Bacteriol 194:2715-24
Eswaramoorthy, Prahathees; Erb, Marcella L; Gregory, James A et al. (2011) Cellular architecture mediates DivIVA ultrastructure and regulates min activity in Bacillus subtilis. MBio 2:

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