The human DINB1 gene encodes the DNA polymerase Poltheta

Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):3838-43. doi: 10.1073/pnas.97.8.3838.


The human DINB1 gene shares a high degree of homology with the Escherichia coli dinB gene. Here, we purify the hDINB1-encoded protein and show that it is a DNA polymerase. Because hDinB1 is the eighth eukaryotic DNA polymerase to be described, we have named it DNA polymerase (Pol) theta. hPoltheta is unable to bypass a cis-syn thymine-thymine dimer, nor does it bypass a (6-4) photoproduct or an abasic site. We also examine the fidelity of hPoltheta on nondamaged DNA templates by steady-state kinetic analyses and find that hPoltheta misincorporates deoxynucleotides with a frequency of about 10(-3) to 10(-4). We discuss the relationship between the fidelity of hPoltheta and its inability to bypass DNA damage.

Publication types

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

MeSH terms

  • Base Sequence
  • Cloning, Molecular
  • DNA Polymerase theta
  • DNA Primers
  • DNA-Directed DNA Polymerase / genetics*
  • DNA-Directed DNA Polymerase / metabolism
  • Humans
  • Kinetics
  • Proteins / genetics*
  • Proteins / metabolism
  • Saccharomyces cerevisiae / genetics


  • DNA Primers
  • Proteins
  • DNA-Directed DNA Polymerase
  • POLK protein, human