title: Budding yeast telomerase RNA transcription termination is dictated by the Nrd1/Nab3 non-coding RNA termination pathway.
abstract: The RNA component of budding yeast telomerase (Tlc1) occurs in two forms, a non-polyadenylated form found in functional telomerase and a rare polyadenylated version with unknown function. Previous work suggested that the functional Tlc1 polyA- RNA is processed from the polyA+ form, but the mechanisms regulating its transcription termination and 3'-end formation remained unclear. Here we examined transcription termination of Tlc1 RNA in the sequences 3' of the TLC1 gene and relate it to telomere maintenance. Strikingly, disruption of all probable or cryptic polyadenylation signals near the 3'-end blocked the accumulation of the previously reported polyA+ RNA without affecting the level, function or specific 3' nucleotide of the mature polyA- form. A genetic approach analysing TLC1 3'-end sequences revealed that transcription terminates upstream of the polyadenylation sites. Furthermore, the results also demonstrate that the function of this Tlc1 terminator depends on the Nrd1/Nab3 transcription termination pathway. The data thus show that transcription termination of the budding yeast telomerase RNA occurs as that of snRNAs and Tlc1 functions in telomere maintenance are not strictly dependent on a polyadenylated precursor, even if the polyA+ form can serve as intermediate in a redundant termination/maturation pathway.
authors.affiliation: RNA Group, Department of Microbiology and Infectious Diseases, Faculty of Medicine, Université de Sherbrooke, 3001, 12e Ave Nord, Sherbrooke, Quebec, J1H 5N4, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Noël
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Larose
authors.forename: Sherif
authors.initials: S
authors.lastname: Abou Elela
authors.forename: Raymund J
authors.initials: RJ
authors.lastname: Wellinger
mesh_terms: D015966:Gene Expression Regulation, Fungal; D009687:Nuclear Proteins / Q000378:metabolism*; D026723:Polyadenylation; D012313:RNA / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D022661:RNA, Untranslated / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D019098:Telomerase / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism
chemical_list: C090564:NAB3 protein, S cerevisiae; C491211:NRD1 protein, S cerevisiae; D009687:Nuclear Proteins; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D029701:Saccharomyces cerevisiae Proteins; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase