title: Pre-spliceosome formation in S.pombe requires a stable complex of SF1-U2AF(59)-U2AF(23).
abstract: We have initiated a biochemical analysis of splicing complexes in extracts from the fission yeast Schizosaccharomyces pombe. Extracts of S.pombe contain high levels of the spliceosome-like U2/5/6 tri-snRNP, which dissociates into mono-snRNPs in the presence of ATP, and supports binding of U2 snRNP to the 3' end of introns, yielding a weak ATP-independent E complex and the stable ATP-dependent complex A. The requirements for S.pombe complex A formation (pre-mRNA sequence elements, protein splicing factors, SF1/BBP and both subunits of U2AF) are analogous to those of mammalian complex A. The S.pombe SF1/BBP, U2AF(59) and U2AF(23) are tightly associated in a novel complex that is required for complex A formation. This pre-formed SF1- U2AF(59)-U2AF(23) complex may represent a streamlined mechanism for recognition of the branch site, pyrimidine tract and 3' splice site at the 3' end of introns.
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461-1975, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Huang
authors.forename: Josep
authors.initials: J
authors.lastname: Vilardell
authors.forename: Charles C
authors.initials: CC
authors.lastname: Query
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D046911:Macromolecular Substances; D008954:Models, Biological; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D021122:Protein Subunits; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017381:Spliceosomes / Q000378:metabolism*; D000072668:Splicing Factor U2AF
chemical_list: D046911:Macromolecular Substances; D009687:Nuclear Proteins; D021122:Protein Subunits; D012322:RNA Precursors; D012331:RNA, Fungal; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; D012261:Ribonucleoproteins; D029702:Schizosaccharomyces pombe Proteins; D000072668:Splicing Factor U2AF; D000255:Adenosine Triphosphate