Format

Send to

Choose Destination
EMBO J. 2000 Nov 15;19(22):6218-29.

Yeast snoRNA accumulation relies on a cleavage-dependent/polyadenylation-independent 3'-processing apparatus.

Author information

1
Istituto Pasteur Fondazione Cenci-Bolognetti, Dipartimento di Genetica e Biologia Molecolare, Università 'La Sapienza' and Centro Acidi Nucleici of CNR, Piazzale A.Moro 5, 00185 Rome, Italy.

Abstract

In Saccharomyces cerevisiae, snoRNAs are encoded by independent genes and within introns. Despite this heterogenous organization, snoRNA biosynthesis relies on a common theme: entry sites for 5'-3' and 3'-5' exonucleases are created on precursor molecules allowing the release of mature snoRNAs. In independently transcribed snoRNAs, such entry sites are often produced by the Rnt1p endonuclease. In many cases, cleavage sites are absent in the 3' portion of the pre-snoRNAs, suggesting that processing starts from the 3' end of the primary transcript. Here we show that cleavage/polyadenylation sites driving efficient polyadenylation, such as CYC1, prevent production of mature and functional snoRNPs. With these sites, snoRNA accumulation is restored only if polyadenylation activity is inhibited. Analysis of sequences downstream of snoRNA-coding units and the use of strains carrying mutations in RNA polymerase II (polII) cleavage/polyadenylation activities allowed us to establish that formation of snoRNA mature 3' ends requires only the cleavage activity of the polII 3'-processing machinery. These data indicate that, in vivo, uncoupling of cleavage and polyadenylation is necessary for an essential cellular biosynthesis.

PMID:
11080167
PMCID:
PMC305823
DOI:
10.1093/emboj/19.22.6218
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center