SOS mutator DNA polymerase IV functions in adaptive mutation and not adaptive amplification.
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.
McKenzie
G J
GJ
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030-3411, USA.
Lee
P L
PL
Lombardo
M J
MJ
Hastings
P J
PJ
Rosenberg
S M
SM
D000222:Adaptation, Physiological / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D020137:Base Pair Mismatch / Q000235:genetics; D001483:Base Sequence; D004258:DNA Polymerase III / Q000378:metabolism; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D016368:Frameshift Mutation / Q000235:genetics; D005784:Gene Amplification / Q000235:genetics*; D005838:Genotype; D007700:Kinetics; D007763:Lac Operon / Q000235:genetics; D016296:Mutagenesis / Q000235:genetics*; D020125:Mutation, Missense / Q000235:genetics; D018384:Oxidative Stress; D010879:Piperazines; D017354:Point Mutation / Q000235:genetics; D011687:Purines; D013014:SOS Response, Genetics / Q000235:genetics*; D017384:Sequence Deletion / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics; D000068677:Sildenafil Citrate; D013450:Sulfones; D014466:Ultraviolet Rays; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004258:DNA Polymerase III; D019951:DNA Polymerase beta; D029968:Escherichia coli Proteins; D010879:Piperazines; D011687:Purines; D012697:Serine Endopeptidases; D000068677:Sildenafil Citrate; D013450:Sulfones; D000099160:LexA Repressor Protein; C094399:DinB protein, E coli