COMPLEX-FORMATION AND FUNCTIONAL VERSATILITY OF MRE11 OF BUDDING YEAST IN RECOMBINATION

Meiotic recombination of S. cerevisiae contains two temporally coupled processes, formation and processing of double-strand breaks (DSBs). M re11 forms a complex with Rad50 and Xrs2, acting as the binding core, and participates in DSB processing. Although these proteins are also i nvolved in DSB formation, Mre11 is not necessarily holding them. The C -terminal region of Mre11 is required only for DSB formation and binds to some meiotic proteins. The N-terminal half specifies nuclease acti vities that are collectively required for DSB processing. Mre11 has a DNA-binding site for DSB formation and another site for DSB processing . It has two regions to bind to Rad50. Mre11 repairs methyl methanesul fonate-induced DSBs by reactions that require the nuclease activities and those that do not.