DNA damage checkpoint activation affects peptidoglycan synthesis and late divisome components in Bacillus subtilis. Issue 2 (25th June 2021)

• Record Type: Journal Article
• Authors: Masser, Emily A.; Burby, Peter E.; Hawkins, Wayne D.; Gustafson, Brooke R.; Lenhart, Justin S.; Simmons, Lyle A.
• Is Part Of: Molecular microbiology. Volume 116:Issue 2(2021)
• Page Start: 707
• Page End: 722
• Publication Date: 2021-06-25
• Subjects: cell division -- DNA damage checkpoint -- FtsW -- YneA; Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.14765
• Languages: English
• ISSNs: 0950-382X

Abstract

Abstract: During normal DNA replication, all cells encounter damage to their genetic material. As a result, organisms have developed response pathways that provide time for the cell to complete DNA repair before cell division occurs. In Bacillus subtilis, it is well established that the SOS‐induced cell division inhibitor YneA blocks cell division after genotoxic stress; however, it remains unclear how YneA enforces the checkpoint. Here, we identify mutations that disrupt YneA activity and mutations that are refractory to the YneA‐induced checkpoint. We find that YneA C‐terminal truncation mutants and point mutants in or near the LysM peptidoglycan binding domain render YneA incapable of checkpoint enforcement. In addition, we develop a genetic method which isolated mutations in the ftsW gene that completely bypassed checkpoint enforcement while also finding that YneA interacts with late divisome components FtsL, Pbp2b, and Pbp1. Characterization of an FtsW variant resulted in considerably shorter cells during the DNA damage response indicative of hyperactive initiation of cell division and bypass of the YneA‐enforced DNA damage checkpoint. With our results, we present a model where YneA inhibits septal cell wall synthesis by binding peptidoglycan and interfering with interaction between late arriving divisome components causing DNA damage checkpoint activation. Abstract : During normal cell division and non‐DNA damaging conditions, the peptidoglycan polymerase FtsW assembles Lipid II into peptidoglycan during septal cell wall synthesis. In this work, we propose a new model for how YneA halts cell division in Bacillus subtilis . Following DNA damage, the SOS‐induced cell division inhibitor YneA interacts with the late divisome proteins FtsL, Pbp2b and Pbp1 as well as binds peptidoglycan through its LysM domain (LysM), inhibiting septal cell wall synthesis and preventing cell division.