title: Pif1 regulates telomere length by preferentially removing telomerase from long telomere ends.
abstract: Telomerase, a ribonucleoprotein complex, is responsible for maintaining the telomere length at chromosome ends. Using its RNA component as a template, telomerase uses its reverse transcriptase activity to extend the 3'-end single-stranded, repetitive telomeric DNA sequence. Pif1, a 5'-to-3' helicase, has been suggested to regulate telomerase activity. We used single-molecule experiments to directly show that Pif1 helicase regulates telomerase activity by removing telomerase from telomere ends, allowing the cycling of the telomerase for additional extension processes. This telomerase removal efficiency increases at longer ssDNA gaps and at higher Pif1 concentrations. The enhanced telomerase removal efficiency by Pif1 at the longer single-stranded telomeric DNA suggests a way of how Pif1 regulates telomerase activity and maintains telomere length.
authors: Department of Chemistry, National Taiwan University, Taiwan.
authors: Jing-Ru
authors: JR
authors: Li
authors: Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taiwan.
authors: Tai-Yuan
authors: TY
authors: Yu
authors: Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taiwan.
authors: I-Chieh
authors: IC
authors: Chien
authors: Institute of Biochemistry and Molecular Biology, National Taiwan University, Taiwan.
authors: Chia-Ying
authors: CY
authors: Lu
authors: Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taiwan Institute of Biochemistry and Molecular Biology, National Taiwan University, Taiwan Institute of Biochemistry and Molecular Biology, National Taiwan University, Taiwan.
authors: Jing-Jer
authors: JJ
authors: Lin
authors: Department of Chemistry, National Taiwan University, Taiwan hwli@ntu.edu.tw.
authors: Hung-Wen
authors: HW
authors: Li
mesh_terms: D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism*; D059505:Telomere Homeostasis
chemical_list: D004277:DNA, Single-Stranded; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; D019098:Telomerase; C085463:PIF1 protein, S cerevisiae; D004265:DNA Helicases