The exosome: a conserved eukaryotic RNA processing complex containing multiple 3'-->5' exoribonucleases.
We identified a complex in S. cerevisiae, the "exosome," consisting of the five essential proteins Rrp4p, Rrp41p, Rrp42p, Rrp43p, and Rrp44p (Dis3p). Remarkably, four of these proteins are homologous to characterized bacterial 3'-->5' exoribonucleases; Rrp44p is homologous to RNase II, while Rrp41p, Rrp42p, and Rrp43p are related to RNase PH. Recombinant Rrp4p, Rrp44p, and Rrp41p are 3'-->5' exoribonucleases in vitro that have distributive, processive, and phosphorolytic activities, respectively. All components of the exosome are required for 3' processing of the 5.8S rRNA. Human Rrp4p is found in a comparably sized complex, and expression of the hRRP4 gene in yeast complements the rrp4-1 mutation. We conclude that the exosome constitutes a highly conserved eukaryotic RNA processing complex.
Pubmed ID: 9390555 RIS Download
Amino Acid Sequence | Exoribonucleases | Fungal Proteins | Genetic Complementation Test | HeLa Cells | Humans | Molecular Sequence Data | Molecular Weight | Multienzyme Complexes | Mutation | RNA Processing, Post-Transcriptional | RNA, Ribosomal, 5.8S | Recombinant Fusion Proteins | Saccharomyces cerevisiae | Saccharomyces cerevisiae Proteins