Yeast transcription termination factor Rtt103 functions in DNA damage response.

YKu70/YKu80 is a heterodimer that is essential for repair of DNA double strand breaks through non-homologous end joining pathway in the yeast Saccharomyces cerevisiae. Yku70/80 proteins are associated with telomeres and are important for maintaining the integrity of telomeres. These proteins protect telomeres from recombination events, nuclease attacks, support the formation of heterochromatin at telomeres and anchor telomeres to the nuclear periphery. To identify components in molecular networks involved in the multiple functions of Yku70/80 complex, we performed a genetic screen for suppressors of yku70 deletion. One of the suppressors identified was RTT103, which encodes a protein implicated in transcription termination. We show that rtt103Δ are sensitive to multiple forms of genome insults and that RTT103 is essential for recovery from DNA double strand breaks in the chromosome. We further show that Rtt103 associates with sites of DNA breaks and hence is likely to play a direct role in response to DNA damage.