TY - JOUR
T1 - RecA protein of Escherichia coli has a third essential role in SOS mutator activity
AU - Sweasy, J. B.
AU - Witkin, E. M.
AU - Sinha, N.
AU - Roegner-Maniscalco, V.
PY - 1990
Y1 - 1990
N2 - The DNA damage-inducible SOS response of Escherichia coli includes an error-prone translesion DNA replication activity responsible for SOS mutagenesis. In certain recA mutant strains, in which the SOS response is expressed constitutively, SOS mutagenesis is manifested as a mutator activity. Like UV mutagenesis, SOS mutator activity requires the products of the umuDC operon and depends on RecA protein for at least two essential activities: facilitating cleavage of LexA repressor to derepress SOS genes and processing UmuD protein to produce a fragment (UmuD') that is active in mutagenesis. To determine whether RecA has an additional role in SOS mutator activity, spontaneous mutability (tryptophan dependence to independence) was measured in a family of nine lexA-defective strains, each having a different recA allele, transformed or not with a plasmid that overproduces either UmuD' alone or both UmuD' and UmuC. The magnitude of SOS mutator activity in these strains, which require neiter of the two known roles of RecA protein, was strongly dependent on the particular RecA allele that was present. We conclude that UmuD'C does not determine the mutation rate independently of RecA and that RecA has a third essential role in SOS mutator activity.
AB - The DNA damage-inducible SOS response of Escherichia coli includes an error-prone translesion DNA replication activity responsible for SOS mutagenesis. In certain recA mutant strains, in which the SOS response is expressed constitutively, SOS mutagenesis is manifested as a mutator activity. Like UV mutagenesis, SOS mutator activity requires the products of the umuDC operon and depends on RecA protein for at least two essential activities: facilitating cleavage of LexA repressor to derepress SOS genes and processing UmuD protein to produce a fragment (UmuD') that is active in mutagenesis. To determine whether RecA has an additional role in SOS mutator activity, spontaneous mutability (tryptophan dependence to independence) was measured in a family of nine lexA-defective strains, each having a different recA allele, transformed or not with a plasmid that overproduces either UmuD' alone or both UmuD' and UmuC. The magnitude of SOS mutator activity in these strains, which require neiter of the two known roles of RecA protein, was strongly dependent on the particular RecA allele that was present. We conclude that UmuD'C does not determine the mutation rate independently of RecA and that RecA has a third essential role in SOS mutator activity.
UR - http://www.scopus.com/inward/record.url?scp=0025314791&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025314791&partnerID=8YFLogxK
U2 - 10.1128/jb.172.6.3030-3036.1990
DO - 10.1128/jb.172.6.3030-3036.1990
M3 - Article
C2 - 2188949
AN - SCOPUS:0025314791
SN - 0021-9193
VL - 172
SP - 3030
EP - 3036
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 6
ER -