title: Est1 protects telomeres and inhibits subtelomeric y'-element recombination.
abstract: In the budding yeast Saccharomyces cerevisiae, the structure and function of telomeres are maintained by binding proteins, such as Cdc13-Stn1-Ten1 (CST), Yku, and the telomerase complex. Like CST and Yku, telomerase also plays a role in telomere protection or capping. Unlike CST and Yku, however, the underlying molecular mechanism of telomerase-mediated telomere protection remains unclear. In this study, we employed both the CDC13-EST1 fusion gene and the separation-of-function allele est1-D514A to elucidate that Est1 provided a telomere protection pathway that was independent of both the CST and Yku pathways. Est1's ability to convert single-stranded telomeric DNA into a G quadruplex was required for telomerase-mediated telomere protection function. Additionally, Est1 maintained the integrity of telomeres by suppressing the recombination of subtelomeric Y' elements. Our results demonstrate that one major functional role that Est1 brings to the telomerase complex is the capping or protection of telomeres.
authors.affiliation: The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China.
authors.forename: Xia-Jing
authors.initials: XJ
authors.lastname: Tong
authors.forename: Qian-Jin
authors.initials: QJ
authors.lastname: Li
authors.forename: Yi-Min
authors.initials: YM
authors.lastname: Duan
authors.forename: Ning-Ning
authors.initials: NN
authors.lastname: Liu
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Zhang
authors.forename: Jin-Qiu
authors.initials: JQ
authors.lastname: Zhou
mesh_terms: D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D054856:G-Quadruplexes; D017353:Gene Deletion; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000235:genetics / Q000378:metabolism*
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C520769:YKU70 protein, S cerevisiae; C520770:YKU80 protein, S cerevisiae; C099024:EST1 protein, S cerevisiae; C509185:EST2 protein, S cerevisiae; D019098:Telomerase