The RecF pathway catalyzes generalized recombination in Escherichia coli that is mutant for recBC, sbcB and sbcC. This pathway operating on conjugational recombination requires the recA, recF, recJ, recN, rec0, recQ, recR, ruvA, ruvB and ruvC genes. In contrast, X mutant for its own recombination genes, int, reda and red& requires only the recA and reg genes to recombine efficiently in recBC sb...

In Escherichia coli, the recovery of replication following disruption by UV-induced DNA damage requires the RecF protein and occurs through a process that involves stabilization of replication fork DNA, resection of nascent DNA to allow the offending lesion to be repaired, and reestablishment of a productive replisome on the DNA. RecF forms a homodimer and contains an ATP binding cassette ATPas...

Single-strand gaps (SSGs) and double-strand breaks (DSBs) are the major initiation sites for recombination. In bacteria, the SSGs are repaired by RecFOR, while the DSBs are processed by RecBCD in gram-negative bacteria and AddAB in gram-positive bacteria. Unexpectedly, instead of recBCD genes, the addAB genes were found in members of the alpha-proteobacteria group (gram negative). Taking Rhizob...

Recombination between tryptophan gene mutations within the trp operon was determined among transductants for an outside linked cysB marker under conditions of repression and derepression. These studies, carried out with recipient strains utilizing the RecBC or RecF pathway, or a combination of these pathways of recombination, demonstrate that transcription of trp genes as regulated by the trp r...

The molecular role of the RecF protein in loading RecA protein onto single-stranded DNA (ssDNA)-binding protein-coated ssDNA has been obscured by the facility with which the RecO and RecR proteins alone perform this function. We now show that RecFOR and RecOR define distinct RecA loading functions that operate optimally in different contexts. RecFOR, but not RecOR, is most effective when RecF(R...

We observed that cells lacking Rep and UvrD, two replication accessory helicases, and the recombination protein RecF are cryo-sensitive on rich medium. We isolated five mutations that suppress this Luria-Bertani (LB)-cryo-sensitivity and show that they map in the genes encoding the RNA polymerase subunits RpoB and RpoC. These rpoB (D444G, H447R and N518D) and rpoC mutants (H113R and P451L) were...

The regions of single-stranded (ss) DNA that result from DNA damage are immediately coated by the ssDNA-binding protein (SSB). RecF pathway proteins facilitate the displacement of SSB from ssDNA, allowing the RecA protein to form protein filaments on the ssDNA region, which facilitates the process of recombinational DNA repair. In this study, we examined the mechanism of SSB displacement from s...

Multiple mutant strains have been tested or their mimicry of the UV-mutagenesis deficiency of a recA single mutant. Revertants to histidine prototrophy and clear plaque mutants of lambda were scored to determine capacity for UV-mutagenesis. Nearly normal capacity was shown by a uvr+ recB- recF- strain, which shows almost no recA-dependent recombination, by uvr- recB+ recF- strains, which show a...