SOS Mutator DNA Polymerase IV Functions in Adaptive Mutation and Not Adaptive Amplification

• Published in: Molecular cell 2001-03, Vol.7 (3), p.571-579
• Main Authors: McKenzie, Gregory J, Lee, Peter L, Lombardo, Mary-Jane, Hastings, P.J, Rosenberg, Susan M
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological - genetics; Bacterial Proteins - genetics; Base Pair Mismatch - genetics; Base Sequence; dinB gene; DNA Polymerase beta - genetics; DNA Polymerase beta - metabolism; DNA Polymerase III - metabolism; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli Proteins; Evolution, Molecular; Frameshift Mutation - genetics; Gene Amplification - genetics; Genotype; Kinetics; lac gene; Lac Operon - genetics; Mutagenesis - genetics; Mutation, Missense - genetics; Oxidative Stress; Piperazines; Point Mutation - genetics; Purines; replicase; Sequence Deletion - genetics; Serine Endopeptidases - genetics; Sildenafil Citrate; SOS Response (Genetics) - genetics; Sulfones; Ultraviolet Rays
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/S1097-2765(01)00204-0

Adaptive point mutation and amplification are induced responses to environmental stress, promoting genetic changes that can enhance survival. A specialized adaptive mutation mechanism has been documented in one Escherichia coli assay, but its enzymatic basis remained unclear. We report that the SOS-inducible, error-prone DNA polymerase (pol) IV, encoded by dinB, is required for adaptive point mutation in the E. coli lac operon. A nonpolar dinB mutation reduces adaptive mutation frequencies by 85% but does not affect adaptive amplification, growth-dependent mutation, or survival after oxidative or UV damage. We show that pol IV, together with the major replicase, pol III, can account for all adaptive point mutations at lac. The results identify a role for pol IV in inducible genetic change.