The
SOS response is a global response to DNA damage in which the
cell cycle is arrested and
DNA repair and mutagenesis are induced. The system involves the
RecA protein (Rad51 in eukaryotes). The RecA protein, stimulated by single-stranded DNA, is involved in the inactivation of the
LexA repressor thereby inducing the response. It is an error-prone repair system that is attributed to mutagenesis.