title: MiR-124 is involved in post-transcriptional regulation of Polypyrimidine tract binding protein 1 (PTBP1) during neural development in the medaka, Oryzias latipes.
abstract: MicroRNAs (miRNAs) comprise a group of small noncoding RNA molecules thought to have contributed to the evolution of vertebrate brain homogeneity and diversity. The miRNA miR-124 is well conserved between invertebrates and vertebrates and is expressed abundantly in the central nervous system (CNS). We identified miR-124 in the medaka, Oryzias latipes, and investigated its role in neural development. The five candidate genes for medaka precursor miR-124 are unlinked on four different chromosomes and differ in nucleotide length. Their sequences suggest that they can generate functional miRNAs through conventional miRNA biogenesis by folding into stem-loop structures. Whole-mount in situ hybridization and northern blotting revealed that mature miR-124 is specifically expressed in the CNS and the eyes starting at two days post-fertilization. We also examined the sequences and expression of medaka Polypyrimidine tract binding protein 1 (Ptbp1), a possible direct target of miR-124. The 3'UTR of medaka Ptbp1 contains predicted binding motifs (target sites) for miR-124. A GFP reporter assay for the target sites or the entire 3'UTR showed that exogenous miR-124 silences PTBP1 expression in vivo. Our study suggests that medaka miR-124 is involved in post-transcriptional regulation of target genes in neural development and that medaka miR-124 homologs may have spatiotemporal roles different from those in other vertebrates.
authors.affiliation: 1 Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Rie
authors.initials: R
authors.lastname: Kusakabe
authors.forename: Kunio
authors.initials: K
authors.lastname: Inoue
authors.forename: Shin
authors.initials: S
authors.lastname: Tochinai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009990:Oryzias / Q000196:embryology*; D038941:Polypyrimidine Tract-Binding Protein / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*
chemical_list: D035683:MicroRNAs; D038941:Polypyrimidine Tract-Binding Protein