Reconstitution of an SOS response pathway: derepression of transcription in response to DNA breaks.
E. coli responds to DNA damage by derepressing the transcription of about 20 genes that make up the SOS pathway. Genetic analyses have shown that SOS induction in response to double-stranded DNA (dsDNA) breaks requires LexA repressor, and the RecA and RecBCD enzymes--proteins best known for their role as initiators of dsDNA break repair and homologous recombination. Here we demonstrate that purified RecA protein, RecBCD enzyme, single-stranded DNA-binding (SSB) protein, and LexA repressor respond to dsDNA breaks in vitro by derepressing transcription from an SOS promoter. Interestingly, derepression is more rapid if the DNA containing the dsDNA break has a chi recombination hot spot (5'-GCTGGTGG-3'), suggesting a novel regulatory role for one of the most overrepresented octamers in the E. coli genome.
Anderson
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DG
Section of Microbiology, University of California, Davis, 95616-8665, USA.
Kowalczykowski
S C
SC
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D019457:Chromosome Breakage / Q000502:physiology; D004249:DNA Damage / Q000502:physiology*; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013014:SOS Response, Genetics / Q000235:genetics*; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D015252:Deoxyribonucleases, Type II Site-Specific; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases; D011938:Rec A Recombinases; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C032824:ATCGAT-specific type II deoxyribonucleases