Amino acid similarities to other proteins offer insights into roles of UmuD and UmuC in mutagenesis.
The products of the umuD and umuC genes are required for most uv and chemical mutagenesis in Escherichia coli. The genes are organized in an operon that is repressed by LexA and regulated as part of the SOS response. The umuD protein shares homology with the carboxyl-terminal domain of LexA. Genetic evidence now indicates that RecA-mediated cleavage activates UmuD for its role in mutagenesis. The COOH-terminal fragment of UmuD is both necessary and sufficient for this role. Similarities of UmuD to gene 45 protein of bacteriophage T4 and of UmuC to gene 44 protein and gene 62 protein suggest possible roles for UmuD and UmuC in mutagenesis that are supported by preliminary evidence.
Battista
J R
JR
Biology Department, Massachusetts Institute of Technology, Cambridge 02139.
Nohmi
T
T
Donnelly
C E
CE
Walker
G C
GC
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D012697:Serine Endopeptidases; D013604:T-Phages / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004259:DNA-Directed DNA Polymerase; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D014764:Viral Proteins; D000099160:LexA Repressor Protein; C055218:UmuD protein, E coli