A mRad51-GFP antimorphic allele affects homologous recombination and DNA damage sensitivity

Evert Jan Uringa, Céline Baldeyron, Hanny Odijk, Evelyne Wassenaar, Wiggert A. van Cappellen, Alex Maas, Jan H.J. Hoeijmakers, Willy M. Baarends, Roland Kanaar, Jeroen Essers

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Accurate DNA double-strand break repair through homologous recombination is essential for preserving genome integrity. Disruption of the gene encoding RAD51, the protein that catalyzes DNA strand exchange during homologous recombination, results in lethality of mammalian cells. Proteins required for homologous recombination, also play an important role during DNA replication. To explore the role of RAD51 in DNA replication and DSB repair, we used a knock-in strategy to express a carboxy-terminal fusion of green fluorescent protein to mouse RAD51 (mRAD51-GFP) in mouse embryonic stem cells. Compared to wild-type cells, heterozygous mRad51+/wt-GFP embryonic stem cells showed increased sensitivity to DNA damage induced by ionizing radiation and mitomycin C. Moreover, gene targeting was found to be severely impaired in mRad51+/wt-GFP embryonic stem cells. Furthermore, we found that mRAD51-GFP foci were not stably associated with chromatin. From these experiments we conclude that this mRad51-GFP allele is an antimorphic allele. When this allele is present in a heterozygous condition over wild-type mRad51, embryonic stem cells are proficient in DNA replication but display defects in homologous recombination and DNA damage repair.

Original languageEnglish
Pages (from-to)27-40
Number of pages14
JournalDNA Repair
Publication statusPublished - 1 Jan 2015
Externally publishedYes


  • DNA repair
  • Embryonic stem cells
  • Homologous recombination
  • RAD51
  • Replication


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