Human replication protein A can suppress the intrinsic in vitro mutator phenotype of human DNA polymerase lambda

Nucleic Acids Res. 2006 Mar 6;34(5):1405-15. doi: 10.1093/nar/gkl032. Print 2006.


DNA polymerase lambda (pol lambda) is a member of the X family DNA polymerases and is endowed with multiple enzymatic activities. In this work we investigated the in vitro miscoding properties of full-length, human pol lambda either in the absence or in the presence of the human auxiliary proteins proliferating cell nuclear antigen (PCNA) and replication protein A (RP-A). Our data suggested that (i) pol lambda had an intrinsic ability to create mismatches and to incorporate ribonucleotides at nearly physiological Mn++ and Mg++ concentrations; (ii) the sequence of the template-primer could influence the misincorporation frequency of pol lambda; (iii) pol lambda preferentially generated G:T and G:G mismatches; (iv) RP-A, but not PCNA, selectively prevented misincorporation of an incorrect nucleotide by pol lambda, without affecting correct incorporation and (v) this inhibitory effect required a precise ratio between the concentrations of pol lambda and RP-A. Possible physiological implications of these findings for the in vivo fidelity of pol lambda are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Pair Mismatch*
  • DNA Polymerase beta / metabolism*
  • Deoxyribonucleotides / metabolism
  • Humans
  • Magnesium / chemistry
  • Manganese / chemistry
  • Phenotype
  • Proliferating Cell Nuclear Antigen / physiology
  • Replication Protein A / physiology*
  • Ribonucleotides / metabolism
  • Templates, Genetic


  • Deoxyribonucleotides
  • Proliferating Cell Nuclear Antigen
  • RPA1 protein, human
  • Replication Protein A
  • Ribonucleotides
  • Manganese
  • DNA polymerase beta2
  • DNA Polymerase beta
  • Magnesium