期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：23
页码：8581-8586
DOI：10.1073/pnas.0402888101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
