ComGA-RelA interaction and persistence in the Bacillus subtilis K-state.

TitleComGA-RelA interaction and persistence in the Bacillus subtilis K-state.
Publication TypeJournal Article
Year of Publication2015
AuthorsHahn, J, Tanner, AW, Carabetta, VJ, Cristea, IM, Dubnau, D
JournalMol Microbiol
Volume97
Issue3
Pagination454-71
Date Published2015
ISSN1365-2958
KeywordsBacillus subtilis, Bacterial Proteins, Cell Division, DNA Transformation Competence, DNA-Binding Proteins, Gene Expression Regulation, Bacterial, Guanosine Pentaphosphate, Guanosine Tetraphosphate, Ligases, Protein Binding, Protein Interaction Mapping, RNA, Ribosomal
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.

DOI10.1111/mmi.13040
Alternate JournalMol. Microbiol.
PubMed ID25899641
PubMed Central IDPMC4722805
Grant ListR01GM057720 / GM / NIGMS NIH HHS / United States
DP1 DA026192 / DA / NIDA NIH HHS / United States
DP1DA026192 / DA / NIDA NIH HHS / United States
R21 HD073044 / HD / NICHD NIH HHS / United States
R01 GM057720 / GM / NIGMS NIH HHS / United States
R21HD073044-01A1 / HD / NICHD NIH HHS / United States