Analysis of the SOS inducing signal in Bacillus subtilis using Escherichia coli LexA as a probe.
We analyzed the Bacillus subtilis SOS response using Escherichia coli LexA protein as a probe to measure the kinetics of SOS activation and DNA repair in wild-type and DNA repair-deficient strains. By examining the effects of DNA-damaging agents that produce the SOS inducing signal in E. coli by three distinct pathways, we obtained evidence that the nature of the SOS inducing signal has been conserved in B. subtilis. In particular, we used the B. subtilis DNA polymerase III inhibitor, 6-(p-hydroxyphenylazo)-uracil, to show that DNA replication is required to generate the SOS inducing signal following UV irradiation. We also present evidence that single-stranded gaps, generated by excision repair, serve as part of the UV inducing signal. By assaying the SOS response in B. subtilis dinA, dinB, and dinC mutants, we identified distinct deficiencies in SOS activation and DNA repair that suggest roles for the corresponding gene products in the SOS response.
Lovett
C M
CM
Department of Chemistry, Williams College, Williamstown, Massachusetts 01267.
O'Gara
T M
TM
Woodruff
J N
JN
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology; D001483:Base Sequence; D004261:DNA Replication; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D011938:Rec A Recombinases / Q000378:metabolism; D013014:SOS Response, Genetics; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012333:RNA, Messenger; D011938:Rec A Recombinases; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C074431:polB protein, E coli