This proposal investigates cell envelope stress responses in Bacillus subtilis, a model organism for the Gram positive bacteria. Antibiotics and other agents that impair the synthesis or function of the cell membrane or peptidoglycan cell wall are of critical importance in clinical medicine. Exposure to sub-lethal levels of antibiotics activates the transcription of sets of genes (cell envelope stress responses) that serve to remodel the cell wall and membrane. In B. subtilis, these stress responses are coordinated by alternative sigma subunits for RNA polymerase of the extracytoplasmic function (ECF) subfamily. This proposal is focused on defining the role of ECF sigma factors in controlling adaptive changes in cell envelope function. One focus will be on the roles of induced lipid biosynthesis pathways and proteins in the genesis and function of lipid rafts. A second focus will be to discover the roles of a newly defined second messenger, cyclic-di-AMP, that is required for cell envelope homeostasis. Using a combination of classical and molecular genetics, genomics, transcriptomics, and biochemical approaches, these studies will provide insights into cell envelope synthesis and function, and reveal novel mechanisms of antibiotic resistance.

Public Health Relevance

The bacterial envelope, comprising a lipid membrane and a peptidoglycan cell wall, separates the cell from the environment and is a target for the majority of antibiotics currently in clinical use. This proposal identifies pathways by which bacteria respond to antibiotic threats by modifying the biosynthesis of the cell envelope with implications for the development of antibiotic resistance. This proposal focuses specifically on the model Gram positive bacterium Bacillus subtilis which is related to Staphylococcus aureus and pathogenic streptococcal and enterococcal strains.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM047446-21A1
Application #
8578417
Study Section
Prokaryotic Cell and Molecular Biology Study Section (PCMB)
Program Officer
Reddy, Michael K
Project Start
1992-05-01
Project End
2017-05-31
Budget Start
2013-08-01
Budget End
2014-05-31
Support Year
21
Fiscal Year
2013
Total Cost
$479,576
Indirect Cost
$163,431
Name
Cornell University
Department
Microbiology/Immun/Virology
Type
Schools of Earth Sciences/Natur
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
Zhao, Heng; Sun, Yingjie; Peters, Jason M et al. (2016) Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis. J Bacteriol 198:2925-2935
Helmann, John D (2016) Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope. Curr Opin Microbiol 30:122-32
Helmann, John D (2015) Molecular scribes in the spotlight: Methods for illuminating Bacterial and Archaeal transcription. Methods 86:1-3
Schirner, Kathrin; Eun, Ye-Jin; Dion, Mike et al. (2015) Lipid-linked cell wall precursors regulate membrane association of bacterial actin MreB. Nat Chem Biol 11:38-45
Helmann, John D (2015) Chemical proteomics reveals a second family of cyclic-di-AMP hydrolases. Proc Natl Acad Sci U S A 112:1921-2
Gaballa, Ahmed; Chi, Bui Khanh; Roberts, Alexandra A et al. (2014) Redox regulation in Bacillus subtilis: The bacilliredoxins BrxA(YphP) and BrxB(YqiW) function in de-bacillithiolation of S-bacillithiolated OhrR and MetE. Antioxid Redox Signal 21:357-67
Lee, Yong Heon; Helmann, John D (2014) Mutations in the primary sigma factor σA and termination factor rho that reduce susceptibility to cell wall antibiotics. J Bacteriol 196:3700-11
Kingston, Anthony W; Zhao, Heng; Cook, Gregory M et al. (2014) Accumulation of heptaprenyl diphosphate sensitizes Bacillus subtilis to bacitracin: implications for the mechanism of resistance mediated by the BceAB transporter. Mol Microbiol 93:37-49
Kashyap, Des Raj; Rompca, Annemarie; Gaballa, Ahmed et al. (2014) Peptidoglycan recognition proteins kill bacteria by inducing oxidative, thiol, and metal stress. PLoS Pathog 10:e1004280
Wright, Gerard D; Hung, Deborah T; Helmann, John D (2013) How antibiotics kill bacteria: new models needed? Nat Med 19:544-5

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