Polyadenylation of rRNA in Saccharomyces cerevisiae

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 101; no. 23; pp. 8581 - 8586
• Main Authors: Kuai, Letian, Fang, Feng, Butler, J. Scott, Sherman, Fred
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 08.06.2004; National Acad Sciences
• Subjects: Base Sequence; Biochemistry; Biological Sciences; Cell Nucleus - metabolism; Enzymes; Exoribonucleases - genetics; Exoribonucleases - metabolism; Exosome Multienzyme Ribonuclease Complex; Fluorescence in situ hybridization; Genes, Fungal; In Situ Hybridization, Fluorescence; Messenger RNA; Poly A - chemistry; Poly A - genetics; Poly A - metabolism; Polyadenylation; Polymerase chain reaction; Polynucleotide Adenylyltransferase - genetics; Polynucleotide Adenylyltransferase - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Reverse transcription; Ribonucleic acid; RNA; RNA precursors; RNA, Fungal - chemistry; RNA, Fungal - genetics; RNA, Fungal - metabolism; RNA, Ribosomal - chemistry; RNA, Ribosomal - genetics; RNA, Ribosomal - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Yeast; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0402888101

In contrast to mRNAs, rRNAs are transcribed by RNA polymerase I or III and are not believed to be polyadenylated. Here we show that in Saccharomyces cerevisiae, at least a small fraction of rRNAs do have a poly(A) tail. The levels of polyadenylated rRNAs are dramatically increased in strains lacking the degradation function of Rrp6p, a component of the nuclear exosome. Pap1p, the poly(A) polymerase, is responsible for adenylating the rRNAs despite the fact that the rRNAs do not have a canonical polyadenylation signal. Polyadenylated rRNAs reside mainly within the nucleus and are in turn degraded. For at least one rRNA type, the polyadenylation preferentially occurs on the precursor rather than the mature product. The existence of polyadenylated rRNAs may reflect a quality-control mechanism of rRNA biogenesis.