Human meiotic recombinase Dmc1 promotes ATP-dependent homologous DNA strand exchange

Michael G. Sehorn, Stefan Sigurdsson, Wendy Bussen, Vinzenz M. Unger, Patrick Sung

Research output: Contribution to journalArticlepeer-review

155 Scopus citations


Homologous recombination is crucial for the repair of DNA breaks and maintenance of genome stability. In Escherichia coli, homologous recombination is dependent on the RecA protein. In the presence of ATP, RecA mediates the homologous DNA pairing and strand exchange reaction that links recombining DNA molecules. DNA joint formation is initiated through the nucleation of RecA onto single-stranded DNA (ssDNA) to form helical nucleoprotein filaments. Two RecA-like recombinases, Rad51 and Dmc1, exist in eukaryotes. Whereas Rad51 is needed for both mitotic and meiotic recombination events, the function of Dmc1 is restricted to meiosis. Here we examine human Dmc1 protein (hDmc1) for the ability to promote DNA strand exchange, and show that hDmc1 mediates strand exchange between paired DNA substrates over at least several thousand base pairs. DNA strand exchange requires ATP and is strongly dependent on the heterotrimeric ssDNA-binding molecule replication factor A (RPA). We present evidence that hDmc1-mediated DNA recombination initiates through the nucleation of hDmc1 onto ssDNA to form a helical nucleoprotein filament. The DNA strand exchange activity of hDmc1 is probably indispensable for repair of DNA double-strand breaks during meiosis and for maintaining the ploidy of meiotic chromosomes.

Original languageEnglish (US)
Pages (from-to)433-437
Number of pages5
Issue number6990
StatePublished - May 27 2004
Externally publishedYes

ASJC Scopus subject areas

  • General


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