Coexpression of UmuD' with UmuC suppresses the UV mutagenesis deficiency of groE mutants.
The GroE proteins of Escherichia coli are heat shock proteins which have also been shown to be molecular chaperone proteins. Our previous work has shown that the GroE proteins of E. coli are required for UV mutagenesis. This process requires the umuDC genes which are regulated by the SOS regulon. As part of the UV mutagenesis pathway, the product of the umuD gene, UmuD, is posttranslationally cleaved to yield the active form, UmuD'. In order to investigate what role the groE gene products play in UV mutagenesis, we measured UV mutagenesis in groE+ and groE strains which were expressing either the umuDC or umuD'C genes. We found that expression of umuD' instead of umuD will suppress the nonmutability conferred by the groE mutations. However, cleavage of UmuD to UmuD' is unaffected by mutations at the groE locus. Instead we found that the presence of UmuD' increased the stability of UmuC in groE strains. In addition, we obtained evidence which indicates that GroEL interacts directly with UmuC.
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
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Walker
D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D018835:Chaperonin 10; D018834:Chaperonin 60; D018833:Chaperonins; D003080:Cold Temperature; D004259:DNA-Directed DNA Polymerase; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics / Q000276:immunology; D008954:Models, Biological; D016296:Mutagenesis / Q000235:genetics* / Q000528:radiation effects; D009154:Mutation / Q000235:genetics; D011499:Protein Processing, Post-Translational; D013014:SOS Response, Genetics / Q000235:genetics; D013489:Suppression, Genetic; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli; D018833:Chaperonins