Hypermethylation of yeast telomerase RNA by the snRNA and snoRNA methyltransferase Tgs1.
Telomerase in Saccharomyces cerevisiae consists of three protein subunits and the RNA moiety TLC1, which together ensure the complete replication of chromosome ends. TLC1 shares several features with snRNA, among them the presence of a trimethylguanosine (m(3)G) cap structure at the 5' end of the RNA. Here, we report that the yeast snRNA and snoRNA methyltransferase Tgs1 is responsible for TLC1 m(3)G cap formation. The absence of Tgs1 caused changes in telomere length and structure, improved telomeric silencing and stabilized telomeric recombination. Genetic analyses implicated a role for the TLC1 m(3)G cap in the coordination between telomerase and DNA polymerase for end replication. Furthermore, tgs1Delta cells displayed a shortened replicative lifespan, suggesting that the loss of the m(3)G cap of TLC1 causes premature aging.
Zentrum für Medizinische Biotechnologie, Universität Duisburg-Essen, Universitätsstr. 5, 45117 Essen, Germany.
Jacqueline
J
Franke
Jessica
J
Gehlen
Ann E
AE
Ehrenhofer-Murray
D000818:Animals; D019175:DNA Methylation; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004330:Drosophila; D020868:Gene Silencing; D006801:Humans; D008780:Methyltransferases / Q000502:physiology*; D008954:Models, Biological; D012313:RNA / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000235:genetics / Q000378:metabolism*; D020537:RNA, Small Nucleolar / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D019098:Telomerase / Q000737:chemistry* / Q000378:metabolism; D016615:Telomere / Q000648:ultrastructure
D012342:RNA, Small Nuclear; D020537:RNA, Small Nucleolar; D012313:RNA; D008780:Methyltransferases; C456271:trimethylguanosine synthase; D019098:Telomerase; D004259:DNA-Directed DNA Polymerase