Characterization of recF suppressors in Bacillus subtilis.

A recF mutation renders Bacillus subtilis cells very sensitive to DNA-damaging agents. Such a recF defect is partially suppressed either by the presence of the recA73 mutation or by the presence of a plasmid-borne, heterologous, single-stranded DNA-binding (ssb) protein gene. Plasmids carrying ssb genes also suppressed the recR and recL defects. Our results suggest that suppression occurs by increasing recombinational repair. The effect of the suppressors may be at the level of induction of the SOS response.