title: Cloning and intracellular localization of the U2 small nuclear ribonucleoprotein auxiliary factor small subunit.
abstract: U2 small nuclear ribonucleoprotein auxiliary factor (U2AF), an essential mammalian splicing factor, is composed of two subunits: a 65-kDa protein (U2AF65), which binds the pre-mRNA polypyrimidine tract and is required for in vitro splicing, and an associated 35-kDa protein (U2AF35). Here we report the isolation of a cDNA encoding U2AF35. U2AF35 contains sequence motifs found in several mammalian pre-mRNA splicing factors. We show directly that U2AF65 and U2AF35 interact with each other and delineate the regions of both proteins that mediate this interaction. Using anti-peptide antibodies against U2AF35, we show that the protein has the intracellular distribution characteristic of U2AF65. Both U2AF65 and U2AF35 are concentrated in a small number of nuclear foci corresponding to coiled bodies, subnuclear organelles first identified by light microscopy in 1903.
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical Center, Worcester 01605.
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: P D
authors.initials: PD
authors.lastname: Zamore
authors.forename: M
authors.initials: M
authors.lastname: Carmo-Fonseca
authors.forename: A I
authors.initials: AI
authors.lastname: Lamond
authors.forename: M R
authors.initials: MR
authors.lastname: Green
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D012342:RNA, Small Nuclear / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear; D000072668:Splicing Factor U2AF
chemical_list: D046911:Macromolecular Substances; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012342:RNA, Small Nuclear; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D000072668:Splicing Factor U2AF; C076753:U2AF1 protein, human