ComGA-RelA interaction and persistence in the Bacillus subtilis K-state. Author Jeanette Hahn, Andrew Tanner, Valerie Carabetta, Ileana Cristea, David Dubnau Publication Year 2015 Type Journal Article Abstract The bistably expressed K-state of Bacillus subtilis is characterized by two distinct features; transformability and arrested growth when K-state cells are exposed to fresh medium. The arrest is manifested by a failure to assemble replisomes and by decreased rates of cell growth and rRNA synthesis. These phenotypes are all partially explained by the presence of the AAA(+) protein ComGA, which is also required for the binding of transforming DNA to the cell surface and for the assembly of the transformation pilus that mediates DNA transport. We have discovered that ComGA interacts with RelA and that the ComGA-dependent inhibition of rRNA synthesis is largely bypassed in strains that cannot synthesize the alarmone (p)ppGpp. We propose that the interaction of ComGA with RelA prevents the hydrolysis of (p)ppGpp in K-state cells, which are thus trapped in a non-growing state until ComGA is degraded. We show that some K-state cells exhibit tolerance to antibiotics, a form of type 1 persistence, and we propose that the bistable expression of both transformability and the growth arrest are bet-hedging adaptations that improve fitness in the face of varying environments, such as those presumably encountered by B. subtilis in the soil. Keywords Gene Expression Regulation, Bacterial, Bacterial Proteins, Protein Binding, Bacillus subtilis, DNA-Binding Proteins, Cell Division, RNA, Ribosomal, Protein Interaction Mapping, DNA Transformation Competence, Guanosine Pentaphosphate, Guanosine Tetraphosphate, Ligases Journal Mol Microbiol Volume 97 Issue 3 Pages 454-71 Date Published 2015 Aug ISSN Number 1365-2958 DOI 10.1111/mmi.13040 Alternate Journal Mol Microbiol PMCID PMC4722805 PMID 25899641 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML