ELG1, a RFC-related gene,
is involved in telomere length regulation.
Sarit Smolikov, Anat Krauskopf
Molecular Microbiology, Tel-Aviv University, Ramat Aviv, Tel Aviv, 69978,
Israel (saritsmol@hotmail.com)
Telomeres are G-rich DNA repeats associated with a multi-protein complex at the ends of eucaryotic chromosomes. Telomeres are replicated by telomerase, whose action is regulated by several mechanisms. Rap1p regulate telomerase negatively by binding Rif1p/Rif2p, while Tel1p and Ku70p/Ku80p are involved in positive regulation of telomere length. Some of the proteins responsible for lagging strand replication are also involved in telomere length regulation. In a screen for genes involved in telomere length regulation we have identified ELG1, a gene whose deletion causes telomere elongation. ELG1 was identified previously as a member of an alternative RFC complex whose deletion elevates recombination. We used genetic methods to define the relationship between ELG1 and other genes responsible for telomere length regulation. We demonstrated that telomere elongation in elg1 is telomerase dependent and recombination independent. Elongation of telomeres in elg1 is associated with elevation of telomeric silencing. Our results show that ELG1 regulate telomere length through different genetic pathway then the pathways of TEL1 and RAP1. In contrast ELG1 and KU70 act in the same pathway of telomere length regulation and Ku70p is epistatic to Elg1p. In addition other genes associated with alternative RFC complex (CHL12 or RAD24) were shown to belong to distinct epistasis groups than ELG1, as expected if these genes participates in an alternative RFC complex.