Support for a Meiotic Recombination Initiation Complex: Interactions among Rec102p, Rec104p, and Spo11p

Abstract

Initiation of meiotic recombination in the yeast Saccharomyces cerevisiae requires at least 10 gene products. The initiation event creates double-strand breaks, which are then processed by other recombination enzymes. A variety of classical observations, such as the existence of recombination nodules, have suggested that the proteins catalyzing recombination form a complex. A variety of lines of evidence indicate that Rad50p, Mre11p, and Xrs2p interact, and genetic data suggesting interactions between Rec102p and Rec104p have been reported. It has recently been shown that Spo11p coimmunoprecipitates with Rec102p in meiosis as well. In this paper, we provide genetic and biochemical evidence that the meiosis-specific proteins Rec102p, Rec104p, and Spo11p all interact with each other in meiosis. Furthermore, we demonstrate that the interaction between Rec102p and Spo11p does not require Rec104p. Likewise, the interaction between Rec104p and Rec102p does not require Spo11p, although Spo11p may stabilize that association. The interactions suggest that Spo11p, Rec102p, and Rec104p may form a trimeric complex during the initiation of recombination.

ACKNOWLEDGMENTS

The initial stages of this work were supported by National Institutes of Health grant R01-GM36846 to R.E.M. The final stages were supported by the University of Iowa. Laura Salem was supported during part of this work by a National Institutes of Health Genetics Predoctoral Training Grant awarded to the Program in Genetics. Both N.M. and M.H. were supported by a Howard Hughes summer undergraduate research fellowship during this work.

We thank Natalie Morey and Martin Hove, who helped characterize the high-copy-number suppressors as part of their Honors Thesis in Biology. We thank Stuart Haring for excellent suggestions on improving the paper.