Genome-wide analysis reveals an unexpected function for the Drosophila splicing factor U2AF50 in the nuclear export of intronless mRNAs.
The protein factor U2AF is an essential component required for pre-mRNA splicing. Mutations identified in the S. pombe large U2AF subunit were used to engineer transgenic Drosophila carrying temperature-sensitive U2AF large subunit alleles. Mutant recombinant U2AF heterodimers showed reduced polypyrimidine tract RNA binding at elevated temperatures. Genome-wide RNA profiling comparing wild-type and mutant strains identified more than 400 genes differentially expressed in the dU2AF50 mutant flies grown at the restrictive temperature. Surprisingly, almost 40% of the downregulated genes lack introns. Microarray analyses revealed that nuclear export of a large number of intronless mRNAs is impaired in Drosophila-cultured cells RNAi knocked down for dU2AF50. Immunopurification of nuclear RNP complexes showed that dU2AF50 associates with intronless mRNAs. These results reveal an unexpected role for the splicing factor dU2AF50 in the nuclear export of intronless mRNAs.
Blanchette
Marco
M
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
Labourier
Emmanuel
E
Green
Richard E
RE
Brenner
Steven E
SE
Rio
Donald C
DC
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D015536:Down-Regulation; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015870:Gene Expression; D016678:Genome; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D017413:Ribonucleoprotein, U2 Small Nuclear; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016415:Sequence Alignment; D000072668:Splicing Factor U2AF; D015854:Up-Regulation
D029721:Drosophila Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; D012261:Ribonucleoproteins; D000072668:Splicing Factor U2AF; C498657:U2AF50 protein, Drosophila