Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Exoribonucleases / chemistry
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Exoribonucleases / genetics
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Exoribonucleases / isolation & purification
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Exoribonucleases / metabolism*
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Fungal Proteins / chemistry
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Fungal Proteins / genetics
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Fungal Proteins / isolation & purification
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Fungal Proteins / metabolism*
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Genetic Complementation Test
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HeLa Cells
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Humans
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Molecular Sequence Data
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Molecular Weight
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Multienzyme Complexes / metabolism*
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Mutation
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RNA Processing, Post-Transcriptional / physiology*
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RNA, Ribosomal, 5.8S / metabolism
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / isolation & purification
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae Proteins*
Substances
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Fungal Proteins
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Multienzyme Complexes
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RNA, Ribosomal, 5.8S
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RRP4 protein, S cerevisiae
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Exoribonucleases
Associated data
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GENBANK/U00061
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GENBANK/X56909
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GENBANK/Z72980
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GENBANK/Z74159
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GENBANK/Z74763