DinI and RecX modulate RecA-DNA structures in Escherichia coli K-12.

TitleDinI and RecX modulate RecA-DNA structures in Escherichia coli K-12.
Publication TypeJournal Article
Year of Publication2007
AuthorsRenzette N, Gumlaw N, Sandler SJ
JournalMol Microbiol
Date Published2007 Jan
KeywordsBacterial Proteins, DNA, Bacterial, Escherichia coli, Escherichia coli Proteins, Gene Expression Regulation, Bacterial, Genes, Bacterial, Rec A Recombinases

RecA plays a central role in recombination, DNA repair and SOS induction through forming a RecA-DNA helical filament. Biochemical observations show that at low ratios to RecA, DinI and RecX stabilize and destabilize RecA-DNA filaments, respectively, and that the C-terminal 17 residues of RecA are important for RecX function. RecA-DNA filament formation was assayed in vivo using RecA-GFP foci formation in log-phase and UV-irradiated cells. In log-phase cells, dinI mutants have fewer foci than wild type and that recX mutants have more foci than wild type. A recADelta17::gfp mutant had more foci like a recX mutant. dinI recX double mutants have the same number of foci as dinI mutants alone, suggesting that dinI is epistatic to recX. After UV treatment, the dinI, recX and dinI recX mutants differed in their ability to form foci. All three mutants had fewer foci than wild type. The dinI mutant's foci persisted longer than wild-type foci. Roles of DinI and RecX after UV treatment differed from those during log-phase growth and may reflect the different DNA substrates, population of proteins or amounts during the SOS response. These experiments give new insight into the roles of these proteins.

Alternate JournalMol. Microbiol.
PubMed ID17163974