ZFIN ID: ZDB-PUB-090928-6
Genomic organization and embryonic expression of miR-430 in medaka (Oryzias latipes): insights into the post-transcriptional gene regulation in early development
Tani, S., Kusakabe, R., Naruse, K., Sakamoto, H., and Inoue, K.
Date: 2010
Source: Gene   449(1-2): 41-49 (Journal)
Registered Authors: Inoue, Kunio, Naruse, Kiyoshi
Keywords: MicroRNA, miR-430, Teleost, Medaka, Primordial germ cells, Post-transcriptional regulation
MeSH Terms:
  • Animals
  • Base Sequence
  • Blotting, Northern
  • Chromosome Mapping
  • Embryo, Nonmammalian/metabolism*
  • Gene Expression Regulation, Developmental*
  • Genome*
  • In Situ Hybridization
  • MicroRNAs/chemistry
  • MicroRNAs/genetics*
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Oryzias/embryology*
  • Oryzias/genetics
  • RNA Processing, Post-Transcriptional*
  • RNA, Untranslated/chemistry
  • RNA, Untranslated/genetics
PubMed: 19770025 Full text @ Gene
MicroRNAs (miRNAs, miRs) are short noncoding RNA molecules that negatively control the target mRNAs by binding to the 3' untranslated region (UTR). Previous studies have demonstrated that miR-430 is encoded by a clustered multigene family and is abundantly expressed in early development. In zebrafish, miR-430 is needed to suppress primordial germ cell (PGC)-specific genes, such as nanos1, in somatic cells. However, the molecular characteristics of the miR-430 family in other teleost species have not been reported, and it is unclear whether such a function of miR-430 in PGC specification is a conserved feature of animals or not. In medaka (Oryzias latipes), a distantly related teleost, it has been suggested that PGC might be established in a different mode of specification from that of zebrafish. We characterized 16 miR-430 precursors in the medaka genomic sequence. These miR-430 genes form clusters on chromosome 4, which might share its evolutionary origin with that of the very large miR-430 clusters in zebrafish chromosome 4. However, none of the medaka miR-430 genes are identical to the zebrafish miR-430 paralogs. Medaka miR-430 expression starts during epiboly and decreases after axis formation. Functional analysis using reporter gene constructs showed that miR-430 repressed protein expression by binding to the 3'UTR of zebrafish TDRD-7. Consistently, the 3'UTR of medaka TDRD7 contains at least two significant candidates for the putative miR-430 binding site. The ubiquitous and early expression of medaka miR-430 and its ability to downregulate GFP:TDRD7 reporter mRNA imply that miR-430 has a conserved role in early embryogenesis. Smaller copy numbers of miR-430 genes and relatively brief expression in medaka might represent the characteristics of this miRNA family in the common ancestor of teleosts. Changes in the relationships between miR-430 and the target mRNA might be related to differences in the localization patterns of PGC-related genes in medaka and zebrafish.