The Rad50 Coiled Coil Domain is indispensable for Mre11 complex functions

The Mre11 complex (Mre11, Rad50, Xrs2 in S. cerevisiae) influences diverse functions in the DNA damage response. The complex comprises the globular DNA binding domain and the Rad50 hook domain which are linked by a long and extended Rad50 coiled coil domain. In this study, rad50 alleles encoding truncations of the coiled coil domain were constructed to determine which Mre11 complex functions required the full length of the coils. These mutations abolished telomere maintenance, meiotic DSB formation, and severely impaired HR, indicating a requirement for long range action. NHEJ, which is likely mediated by the Mre11 complex globular domain was also severely impaired by alteration of the coiled coil and hook domains, providing the first evidence of their influence on this process. These data show that Mre11 complex functions are integrated by the coiled coils of Rad50.