Comparative gene expression profiles following UV exposure in wild-type and SOS-deficient Escherichia coli.
The SOS response in UV-irradiated Escherichia coli includes the upregulation of several dozen genes that are negatively regulated by the LexA repressor. Using DNA microarrays containing amplified DNA fragments from 95.5% of all open reading frames identified on the E. coli chromosome, we have examined the changes in gene expression following UV exposure in both wild-type cells and lexA1 mutants, which are unable to induce genes under LexA control. We report here the time courses of expression of the genes surrounding the 26 documented lexA-regulated regions on the E. coli chromosome. We observed 17 additional sites that responded in a lexA-dependent manner and a large number of genes that were upregulated in a lexA-independent manner although upregulation in this manner was generally not more than twofold. In addition, several transcripts were either downregulated or degraded following UV irradiation. These newly identified UV-responsive genes are discussed with respect to their possible roles in cellular recovery following exposure to UV irradiation.
Courcelle
J
J
Department of Biochemistry, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA. jcourcelle@biology.msstate.edu
Khodursky
A
A
Peter
B
B
Brown
P O
PO
Hanawalt
P C
PC
D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000528:radiation effects*; D020869:Gene Expression Profiling; D020411:Oligonucleotide Array Sequence Analysis; D013014:SOS Response, Genetics; D012697:Serine Endopeptidases / Q000235:genetics; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein