SOS and Mayday: multiple inducible mutagenic pathways in Escherichia coli


  • M. Zafri Humayun

    1. Department of Microbiology and Molecular Genetics, UMDNJ — New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103-2714, USA.
    Search for more papers by this author

M. Zafri Humayun. E-mail; Tel. (973) 972 5217; Fax (973) 972 3644.


Environmental and physiological stress conditions can transiently alter the fidelity of DNA replication. The DNA damage-mediated SOS response in Escherichia coli is the best-known example of such an ‘inducible mutagenesis’ or ‘transient mutator’ pathway. Emerging evidence suggests the existence of a number of other stress-inducible pathways that also affect the fidelity of replication. Among the more provocative recent findings are UVM, an SOS-independent damage-inducible mutagenic pathway, and a new recA-dependent but umuD/C-independent pathway that appears to be provoked by translational stress. These findings alter our view of inducible mutagenesis, and anticipate the existence of previously unrecognized links between protein synthesis and DNA replication.