Dominant negative umuD mutations decreasing RecA-mediated cleavage suggest roles for intact UmuD in modulation of SOS mutagenesis
- Massachusetts Inst. of Tech., Cambridge, (USA)
The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli. The UmuD protein shares homology with a family of proteins that includes LexA and several bacteriophage repressors. UmuD is posttranslationally activated for its role n mutagenesis by a RecA-mediated proteolytic cleavage that yields UmuD{prime}. A set of missense mutants of umuD was isolated and shown to encode mutant UmuD proteins that are deficient in RecA-mediated cleavage in vivo. Most of these mutations are dominant to umuD{sup +} with respect to UV mutagenesis yet do not interfere with SOS induction. Although both UmuD and UmuD{prime} form homodimers, the authors provide evidence that they preferentially form heterodimers. The relationship of UmuD to LexA, {lambda} repressor, and other members of the family of proteins is discussed and possible roles intact UmuD in modulating SOS mutagenesis are discussed.
- OSTI ID:
- 5460000
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 87:18; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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