Meiotic roles of Mec1, a budding yeast homolog of mammalian ATR/ATM

Budding yeast Mec1, a homolog of mammalian ATR/ATM, is an essential chromosome-based signal transduction protein. Mec1 is a key checkpoint regulator and plays a critical role in the maintenance of genome stability. Mec1 is also required for meiosis; loss of Mec1 functions leads to a number of meiotic defects including reduction in recombination, loss of inter-homolog bias, loss of crossover control, and failure in meiotic progression. Here we review currently available data on meiotic defects associated with loss of Mec1 functions and discuss the possibility that Mec1 may participate as a fundamentally positive player in coordinating and promoting basic meiotic chromosomal processes during normal meiosis.