DNA polymerase beta is critical for genomic stability of sperm cells

DNA Repair (Amst). 2011 Apr 3;10(4):390-7. doi: 10.1016/j.dnarep.2011.01.003. Epub 2011 Feb 18.

Abstract

Maintaining genome integrity in germ cells is important, given that the germ cells produce the next generation of offspring. Base excision repair is a DNA repair pathway that is responsible for the repair of most endogenous DNA damage. A key enzyme that functions in this repair pathway is DNA polymerase beta (Pol β). We previously used conditional gene targeting to engineer mice with sperm deleted of the Pol B gene, which encodes Pol β. We characterized mutagenesis in the sperm of these mice and compared it to wild-type and mice heterozygous for the Pol B gene. We found that sperm obtained that were heterozygously or homozygously deleted of the Pol B gene exhibited increased mutation frequencies compared to wild-type sperm. We identified an increase in transition mutations in both heterozygously and homozygously deleted sperm, and the types of mutations induced suggest that a polymerase other than Pol β functions in its absence. Interestingly, most of the transversions we observed were induced only in heterozygous, compared with wild-type sperm. Our results suggest that haploinsufficiency of Pol β leads to increased frequencies and varieties of mutations. Our study also shows that Pol β is critical for genome stability in the germline.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Base Sequence
  • DNA Damage
  • DNA Polymerase beta / genetics
  • DNA Polymerase beta / metabolism*
  • DNA Repair
  • Enzyme Activation / physiology
  • Genomic Instability*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Molecular Sequence Data
  • Mutation
  • Spermatozoa / metabolism*

Substances

  • DNA Polymerase beta