Abstract
We have partially purified the U2 snRNP of Saccharomyces cerevisiae. Identification of some proteins consistently found in the purified fractions by nanoelectrospray mass spectrometry indicated the presence of a novel splicing factor named Rse1p. The RSE1 gene is essential and codes for a 148.2 kDa protein. We demonstrated that Rse1p associates specifically with U2 snRNA at low salt concentrations. In addition, we showed that Rse1p is a component of the pre-spliceosome. Depletion of Rse1p and analysis of a conditional mutant indicated that Rse1p was required for efficient splicing in vivo. In vitro Rse1p is required for the formation of pre-spliceosomes. Database searches revealed that Rse1p is conserved in humans and that it belongs to a large protein family that includes polyadenylation factors and DNA repair proteins. The characteristics of Rse1p suggest that its human homologue could be a subunit of the SF3 splicing factor.
MeSH terms
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Amino Acid Sequence
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Animals
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Conserved Sequence / genetics
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DNA Repair / genetics
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Fungal Proteins / analysis
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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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Genes, Essential / genetics
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Genes, Fungal / genetics
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Humans
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Molecular Sequence Data
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Molecular Weight
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Mutation
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Open Reading Frames / genetics
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RNA Splicing / genetics*
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RNA, Small Nuclear / genetics
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RNA, Small Nuclear / metabolism
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RNA-Binding Proteins / analysis
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RNA-Binding Proteins / chemistry
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / isolation & purification
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RNA-Binding Proteins / metabolism*
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Ribonucleoprotein, U2 Small Nuclear / chemistry*
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Ribonucleoprotein, U2 Small Nuclear / isolation & purification
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Saccharomyces cerevisiae / chemistry
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins*
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Salts / pharmacology
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Sequence Alignment
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Spliceosomes / chemistry
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Spliceosomes / metabolism*
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mRNA Cleavage and Polyadenylation Factors
Substances
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Fungal Proteins
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RNA, Small Nuclear
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RNA-Binding Proteins
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RSE1 protein, S cerevisiae
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Ribonucleoprotein, U2 Small Nuclear
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Saccharomyces cerevisiae Proteins
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Salts
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mRNA Cleavage and Polyadenylation Factors