Polyadenylation of telomerase RNA in budding yeast.
Telomerase RNA is a subunit of a stable ribonucleoprotein particle required for telomere replication. We find that, at steady state, 5-10% of the telomerase RNA in Saccharomyces cerevisiae and Kluyveromyces lactis contains a poly(A) tail of about 80 nt. In S. cerevisiae, the poly(A)+ fraction quickly disappeared when a conditional pap1 or rna15 mutant was shifted to the nonpermissive temperature, indicating that polyadenylation is accomplished by the same machinery that polyadenylates mRNAs. Potential cis-acting polyadenylation elements were identified in the telomerase RNA sequence; when they were mutagenized, the polyadenylation pattern shifted, but was not eliminated. The corresponding mutants displayed wild-type growth. By putting the RNA under the control of an inducible promoter, we were able to show that synthesis of the poly(A)+ RNA precedes that of the poly(A)- fraction. This supports, but does not prove, a model in which all telomerase RNA is first polyadenylated and then rapidly processed to give the stable poly(A)-form. Cell cycle arrest experiments showed an increase in the poly(A)+ form between G1 and S phase, consistent with an induction of telomerase RNA transcription at the time of DNA replication.
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Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder 80309, USA.
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D001483:Base Sequence; D016193:G1 Phase; D007716:Kluyveromyces / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D000073718:Pancreatitis-Associated Proteins; D011061:Poly A / Q000378:metabolism*; D012331:RNA, Fungal / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D019098:Telomerase / Q000235:genetics*; D014158:Transcription, Genetic
D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D012331:RNA, Fungal; D011061:Poly A; D019098:Telomerase