Targeting of human DNA polymerase iota to the replication machinery via interaction with PCNA

Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14256-61. doi: 10.1073/pnas.261560798. Epub 2001 Nov 27.


Human DNA polymerase iota (hPoliota) promotes translesion synthesis by inserting nucleotides opposite highly distorting or noninstructional DNA lesions. Here, we provide evidence for the physical interaction of hPoliota with proliferating cell nuclear antigen (PCNA), and show that PCNA, together with replication factor C (RFC) and replication protein A (RPA), stimulates the DNA synthetic activity of hPoliota. In the presence of these protein factors, on undamaged DNA, the efficiency (V(max)/K(m)) of correct nucleotide incorporation by hPoliota is increased approximately 80-150-fold, and this increase in efficiency results from a reduction in the apparent K(m) for the nucleotide. PCNA, RFC, and RPA also stimulate nucleotide incorporation opposite the 3'-T of the (6) thymine-thymine (T-T) photoproduct and opposite an abasic site. The interaction of hPoliota with PCNA implies that the targeting of this polymerase to the replication machinery stalled at a lesion site is achieved via this association.

Publication types

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

MeSH terms

  • Base Sequence
  • Binding Sites
  • DNA / biosynthesis
  • DNA / genetics
  • DNA Damage
  • DNA Polymerase iota
  • DNA Primers / genetics
  • DNA Replication / physiology*
  • DNA-Binding Proteins / metabolism
  • DNA-Directed DNA Polymerase / metabolism*
  • Humans
  • In Vitro Techniques
  • Kinetics
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides / metabolism
  • Proliferating Cell Nuclear Antigen / metabolism*
  • Replication Protein A
  • Replication Protein C


  • DNA Primers
  • DNA-Binding Proteins
  • Oligodeoxyribonucleotides
  • Proliferating Cell Nuclear Antigen
  • RPA1 protein, human
  • Replication Protein A
  • DNA
  • DNA-Directed DNA Polymerase
  • Replication Protein C
  • DNA Polymerase iota
  • POLI protein, human