title: Position-dependent and neuron-specific splicing regulation by the CELF family RNA-binding protein UNC-75 in Caenorhabditis elegans.
abstract: A large fraction of protein-coding genes in metazoans undergo alternative pre-mRNA splicing in tissue- or cell-type-specific manners. Recent genome-wide approaches have identified many putative-binding sites for some of tissue-specific trans-acting splicing regulators. However, the mechanisms of splicing regulation in vivo remain largely unknown. To elucidate the modes of splicing regulation by the neuron-specific CELF family RNA-binding protein UNC-75 in Caenorhabditis elegans, we performed deep sequencing of poly(A)(+) RNAs from the unc-75(+)- and unc-75-mutant worms and identified more than 20 cassette and mutually exclusive exons repressed or activated by UNC-75. Motif searches revealed that (G/U)UGUUGUG stretches are enriched in the upstream and downstream introns of the UNC-75-repressed and -activated exons, respectively. Recombinant UNC-75 protein specifically binds to RNA fragments carrying the (G/U)UGUUGUG stretches in vitro. Bi-chromatic fluorescence alternative splicing reporters revealed that the UNC-75-target exons are regulated in tissue-specific and (G/U)UGUUGUG element-dependent manners in vivo. The unc-75 mutation affected the splicing reporter expression specifically in the nervous system. These results indicate that UNC-75 regulates alternative splicing of its target exons in neuron-specific and position-dependent manners through the (G/U)UGUUGUG elements in C. elegans. This study thus reveals the repertoire of target events for the CELF family in the living organism.
authors: Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan. kuroyana.end@tmd.ac.jp
authors: Hidehito
authors: H
authors: Kuroyanagi
authors: Yohei
authors: Y
authors: Watanabe
authors: Yutaka
authors: Y
authors: Suzuki
authors: Masatoshi
authors: M
authors: Hagiwara
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D005091:Exons; D059014:High-Throughput Nucleotide Sequencing; D007438:Introns; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000737:chemistry; D016601:RNA-Binding Proteins / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid; D017423:Sequence Analysis, RNA
chemical_list: D029742:Caenorhabditis elegans Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; C581735:UNC-75 protein, C elegans