The dinB gene encodes a novel E. coli DNA polymerase, DNA pol IV, involved in mutagenesis.
In Escherichia coli, the dinB gene is required for the SOS-induced lambda untargeted mutagenesis pathway and confers a mutator phenotype to the cell when the gene product is overexpressed. Here, we report that the purified DinB protein is a DNA polymerase. This novel E. coli DNA polymerase (pol IV) is shown to be strictly distributive, devoid of proofreading activity, and prone to elongate bulged (misaligned) primer/template structures. Site-directed mutagenesis experiments of dinB also demonstrate that the polymerase activity of DinB is required for its in vivo mutagenicity. Along with the sequence homologies previously found within the UmuC-like protein family, these results indicate that the uncovered DNA polymerase activity may be a common feature of all these homologous proteins.
Wagner
J
J
Division of Genetics and Mutagenesis, National Institute of Health Sciences, Tokyo, Japan.
Gruz
P
P
Kim
S R
SR
Yamada
M
M
Matsui
K
K
Fuchs
R P
RP
Nohmi
T
T
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D019951:DNA Polymerase beta / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000528:radiation effects; D029968:Escherichia coli Proteins; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D013014:SOS Response, Genetics; D013379:Substrate Specificity; D013698:Templates, Genetic; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; C094399:DinB protein, E coli; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D019951:DNA Polymerase beta