XB-ART-34501Dev Dyn August 1, 2006; 235 (8): 2185-91.
The microRNAs (miRNAs) are recently discovered short, noncoding RNAs, that regulate gene expression in metazoans. We have cloned short RNAs from chicken embryos and identified five new chicken miRNA genes. Genome analysis identified 17 new chicken miRNA genes based on sequence homology to previously characterized mouse miRNAs. Developmental Northern blots of chick embryos showed increased accumulation of most miRNAs analyzed from 1.5 days to 5 days except, the stem cell-specific mir-302, which was expressed at high levels at early stages and then declined. In situ analysis of mature miRNAs revealed the restricted expression of mir-124 in the central nervous system and of mir-206 in developing somites, in particular the developing myotome. In addition, we investigated how miR-206 expression is controlled during somite development using bead implants. These experiments demonstrate that fibroblast growth factor (FGF) -mediated signaling negatively regulates the initiation of mir-206 gene expression. This may be mediated through the effects of FGF on somite differentiation. These data provide the first demonstration that developmental signaling pathways affect miRNA expression. Thus far, miRNAs have not been studied extensively in chicken embryos, and our results show that this system can complement other model organisms to investigate the regulation of many other miRNAs.
PubMed ID: 16804893
Article link: Dev Dyn
Species referenced: Xenopus laevis
Genes referenced: fgf4
Article Images: [+] show captions
|Fig. 3. The mir-206 is expressed in somites of chick, mouse, and Xenopus embryos. A�F: Locked nucleic acid (LNA) probe was used to show mir-206 expression in chick Hamburger and Hamilton (HH) stage 17 (A�E) and HH21 (F) embryos; small arrowheads in A indicate mir-206 expression in the lateral myotome. B�E: Transverse sections through the trunk of an HH17 embryo, arrowheads in A indicate the axial levels; in C,E, higher magnification shows staining in the myotome. G,I�K: Somite specific expression of mir-206 in an embryonic day (E) 10 mouse embryo (G) and a stage 35 Xenopus laevis tadpole (I�K); the arrow in I indicates the lack of mir-206 expression in the heart. Section through the trunk shows somite staining (J); K is a higher magnification of I. H: Somite- and heart-specific expression of mir-1 in an E10 mouse embryo the arrow indicates the heart. fl; forelimb, ht, heart; hl, hind limb.|