Partial purification of the yeast U2 snRNP reveals a novel yeast pre-mRNA splicing factor required for pre-spliceosome assembly.
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.
Caspary
F
F
EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
Shevchenko
A
A
Wilm
M
M
Séraphin
B
B
D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D020043:Genes, Essential / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics*; D012342:RNA, Small Nuclear / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000737:chemistry* / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts / Q000494:pharmacology; D016415:Sequence Alignment; D017381:Spliceosomes / Q000737:chemistry / Q000378:metabolism*; D039221:mRNA Cleavage and Polyadenylation Factors
D005656:Fungal Proteins; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; C120617:RSE1 protein, S cerevisiae; D017413:Ribonucleoprotein, U2 Small Nuclear; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts; D039221:mRNA Cleavage and Polyadenylation Factors