Detection and characterization of mammalian DNA polymerase beta mutants by functional complementation in Escherichia coli

Proc Natl Acad Sci U S A. 1993 May 15;90(10):4626-30. doi: 10.1073/pnas.90.10.4626.


We have designed and utilized a bacterial complementation system to identify and characterize mammalian DNA polymerase beta mutants. In this complementation system, wild-type rat DNA polymerase beta replaces both the replicative and repair functions of DNA polymerase I in the Escherichia coli recA718 polA12 double mutant; our 263 DNA polymerase beta mutants replace E. coli polymerase I less efficiently or not at all. Of the 10 mutants that have been shown to contain DNA sequence alterations, 2 exhibit a split phenotype with respect to complementation of the growth defect and methylmethanesulfonate sensitivity of the double mutant; one is a null mutant. The mutants possessing a split phenotype contain amino acid residue alterations within a putative nucleotide binding site of DNA polymerase beta. This approach for the isolation and evaluation of mutants of a mammalian DNA polymerase in E. coli may ultimately lead to a better understanding of the mechanism of action of this enzyme and to precisely defining its role in vertebrate cells.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA Polymerase I / genetics*
  • DNA Repair
  • DNA Replication
  • Escherichia coli / genetics
  • Genes
  • Genetic Complementation Test
  • Molecular Sequence Data
  • Mutagenesis
  • Oligodeoxyribonucleotides / chemistry
  • Rats


  • Oligodeoxyribonucleotides
  • DNA Polymerase I