A DNA damage response pathway controlled by Tel1 and the Mre11 complex

We define a DNA damage checkpoint pathway in S. cerevisiae governed by the ATM homolog Tell and the Mre11 complex. In mitotic cells, the Tel1-Mre11 complex pathway triggers Rad53 activation and its interaction with Rad9, whereas in meiosis it acts via Rad9 and the Rad53 paralog Mre4/Mek1. Activation of the Tel1-Mre11 complex pathway checkpoint functions appears to depend upon the Mre11 complex as a damage sensor and, at least in meiotic cells, to depend on unprocessed DNA double-strand breaks (DSBs). The DSB repair functions of the Mre11 complex are enhanced by the pathway, suggesting that the complex both initiates and is regulated by the Tell dependent DSB signal. These findings demonstrate that the diverse functions of the Mre11 complex in the cellular DNA damage response are conserved in mammals and yeast.