FGF‐4 signaling is involved in mir‐206 expression in developing somites of chicken embryos

Abstract

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. Developmental Dynamics 235:2185-2191, 2006.

The Myogenic Regulatory Factors: Critical Determinants of Muscle Identity in Development, Growth and Regeneration

“…Grafting of FGF4 or FGF8 beads adjacent to somites leads to the loss of expression of MyoD and other myogenic markers [55,56] but induces the expression of the tendon marker scleraxis. However later in somite development FGF from the myotome induces epithelial to mesenchymal transition and translocation of dermomytomal cells into the central region of the myotome [57], a process known to contribute to the satellite cells of the adult [58].…”

miRNAs Regulate miRNAs: Coordinated Transcriptional and Post-Transcriptional Regulation

“…Are miRNAs so low-specific? Despite the fact that the complementarity required for miRNA function is in many cases low, their extremely localized and time-regulated expression [9][10][11] confers to many of them a specific role in gene expression regulation. It comes out clear that microRNA expression must be tightly regulated, because it has to be restricted to particular developmental stages or cell types.…”

Fibroblast Growth Factor (FGF) Signaling during Gastrulation Negatively Modulates the Abundance of MicroRNAs That Regulate Proteins Required for Cell Migration and Embryo Patterning

“…Inhibition of FGFR1 during zebrafish fin regeneration led to the down-regulation of 22 miRs and up-regulation of 34 miRs (52). In chicken embryos, miR-206 is repressed by FGF4 in somatic skeletal muscle cells (53). It is not known whether the FGF-dependent reduction in miR levels in these two studies is mediated by increased expression of LIN28A or LIN28B.…”