RecA-dependent mutants in Escherichia coli reveal strategies to avoid chromosomal fragmentation.

ABSTRACT: RecA- and RecBC-catalyzed repair in eubacteria assembles chromosomes fragmented by double-strand breaks. We propose that recA mutants, being unable to repair fragmented chromosomes, depend on various strategies designed to avoid chromosomal fragmentation. To identify chromosomal fragmentation-avoidance strategies, we screened for Escherichia coli mutants synthetically inhibited in combination with recA inactivation by identifying clones unable to lose a plasmid carrying the recA(+) gene. Using this screen, we have isolated several RecA-dependent mutants and assigned them to three distinct areas of metabolism. The tdk and rdgB mutants affect synthesis of DNA precursors. The fur, ubiE, and ubiH mutants are likely to have increased levels of reactive oxygen species. The seqA, topA mutants and

SUBMITTER: Kouzminova EA 

PROVIDER: S-EPMC528955 | biostudies-literature | 2004 Nov

REPOSITORIES: biostudies-literature