FIG. 5.

The nuclease activity of the MRN complex is necessary for Rec12-oligonucleotide formation. (A) Meiotic induction of nuclease-deficient mutant rad32-D65N mutant strain GP6677. Samples were treated as described for Fig. 1. “+” indicates rad32⁺ cell extract of strain GP6010 at 4 h. Filled arrowhead, ³²P-labeled Rec12-oligonucleotide complex; open arrowhead, Rec12-free protein. (B) DSB analysis of DNA from the meiotic induction shown in panel A. Arrows, chromosome I NotI fragment J (top) and its two prominent DNA fragments broken at meiotic break sites mbs1 and mbs2.