title: Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis.
abstract: The integrity of the bacterial cell envelope is essential to sustain life by countering the high turgor pressure of the cell and providing a barrier against chemical insults. In Bacillus subtilis, synthesis of both peptidoglycan and wall teichoic acids requires a common C55lipid carrier, undecaprenyl-pyrophosphate (UPP), to ferry precursors across the cytoplasmic membrane. The synthesis and recycling of UPP requires a phosphatase to generate the monophosphate form Und-P, which is the substrate for peptidoglycan and wall teichoic acid synthases. Using an optimized clustered regularly interspaced short palindromic repeat (CRISPR) system with catalytically inactive ("dead") CRISPR-associated protein 9 (dCas9)-based transcriptional repression system (CRISPR interference [CRISPRi]), we demonstrate that B. subtilis requires either of two UPP phosphatases, UppP or BcrC, for viability. We show that a third predicted lipid phosphatase (YodM), with homology to diacylglycerol pyrophosphatases, can also support growth when overexpressed. Depletion of UPP phosphatase activity leads to morphological defects consistent with a failure of cell envelope synthesis and strongly activates the σM-dependent cell envelope stress response, including bcrC, which encodes one of the two UPP phosphatases. These results highlight the utility of an optimized CRISPRi system for the investigation of synthetic lethal gene pairs, clarify the nature of the B. subtilis UPP-Pase enzymes, and provide further evidence linking the σMregulon to cell envelope homeostasis pathways.
  
  
  
  The emergence of antibiotic resistance among bacterial pathogens is of critical concern and motivates efforts to develop new therapeutics and increase the utility of those already in use. The lipid II cycle is one of the most frequently targeted processes for antibiotics and has been intensively studied. Despite these efforts, some steps have remained poorly defined, partly due to genetic redundancy. CRISPRi provides a powerful tool to investigate the functions of essential genes and sets of genes. Here, we used an optimized CRISPRi system to demonstrate functional redundancy of two UPP phosphatases that are required for the conversion of the initially synthesized UPP lipid carrier to Und-P, the substrate for the synthesis of the initial lipid-linked precursors in peptidoglycan and wall teichoic acid synthesis.
authors.affiliation: Cornell University, Department of Microbiology, Ithaca, New York, USA.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Molecular and Cellular Biology Department and Faculty of Arts and Sciences (FAS) Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Microbiology and Immunology, University of California, San Francisco, California, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Peters
authors.affiliation: Department of Microbiology and Immunology, University of California, San Francisco, California, USA.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Gross
authors.affiliation: Molecular and Cellular Biology Department and Faculty of Arts and Sciences (FAS) Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA.
authors.forename: Ethan C
authors.initials: EC
authors.lastname: Garner
authors.affiliation: Cornell University, Department of Microbiology, Ithaca, New York, USA jdh9@cornell.edu.
authors.forename: John D
authors.initials: JD
authors.lastname: Helmann
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002473:Cell Wall / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D011106:Polyisoprenyl Phosphates / Q000378:metabolism; D011755:Pyrophosphatases / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011106:Polyisoprenyl Phosphates; C088139:undecaprenyl pyrophosphate; D011755:Pyrophosphatases; C503879:undecaprenyl pyrophosphate phosphatase