title: Splicing factor SF1 from Drosophila and Caenorhabditis: presence of an N-terminal RS domain and requirement for viability.
abstract: Splicing factor SF1 contributes to the recognition of the 3' splice site by interacting with U2AF65 and binding to the intron branch site during the formation of the early splicing complex E. These interactions and the essential functional domains of SF1 are highly conserved in Saccharomyces cerevisiae. We have isolated cDNAs encoding SF1 from Drosophila (Dm) and Caenorhabditis (Ce). The encoded proteins share the U2AF65 interaction domain, a hnRNP K homology domain, and one or two zinc knuckles required for RNA binding as well as Pro-rich C-terminal sequences with their yeast and mammalian counterparts. In contrast to SF1 in other species, DmSF1 and CeSF1 are characterized by an N-terminal region enriched in Ser, Arg, Lys, and Asp residues with homology to the RS domains of several splicing proteins. These domains mediate protein-protein or protein-RNA interactions, suggesting an additional role for DmSF1 and CeSF1 in pre-mRNA splicing. Human (Hs), fly, and worm SF1 interact equally well with HsU2AF65 or the Drosophila homolog DmU2AF50. Moreover, DmSF1 lacking its N terminus is functional in prespliceosome formation in a HeLa splicing system, emphasizing the conserved nature of interactions at an early step in spliceosome assembly. The Ce-SF1 gene is located in a polycistronic transcription unit downstream of the genes encoding U2AF35 (uaf-2) and a cyclophilin (cyp-13), implying the coordinate transcriptional regulation of these genes. Injection of double-stranded RNA into C. elegans results in embryonic lethality; thus, the SF1 gene is essential not only in yeast but also in at least one metazoan.
authors.affiliation: Département de Biologie Cellulaire, Université de Genève, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Mazroui
authors.forename: A
authors.initials: A
authors.lastname: Puoti
authors.forename: A
authors.initials: A
authors.lastname: Krämer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002107:Caenorhabditis / Q000235:genetics*; D002460:Cell Line; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008969:Molecular Sequence Data; D011392:Proline; D012326:RNA Splicing; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D016335:Zinc Fingers
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D017411:Ribonucleoproteins, Small Nuclear; C491517:SF1 protein, Drosophila; C491516:SF1 protein, S cerevisiae; C107467:SF1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011392:Proline