Biomedical subjects

Terence G Smith

Publications and source records attributed to Terence G Smith.

3 recordsLinked to original sources

PubMed2006

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

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.

Animals↗

PubMed2006

The expression of Flrt3 during chick limb development.

The Flrt3 (Fibronectin-Leucine-Rich Transmembrane protein) gene encodes a fibronectin and leucine-rich repeat transmembrane protein whose expression is controlled by fibroblast growth factors (FGFs). FLRT3 has been implicated in neurite outgrowth after nerve damage, as a positive regulator of FGF signalling and in homotypic cell adhesion. Here we describe Flrt3 expression during chick embryonic limb development using whole-mount in situ hybridization. We found very dynamic expression during apical ridge formation and limb bud outgrowth. Initially Flrt3 is expressed in the apical ectodermal ridge and underlying mesenchyme, but then becomes restricted to the dorsal and ventral sides of the apical ridge as a twin stripe. At later stages, abundant expression is seen in the hindlimb and in both the pectoral and pelvic girdle-forming regions. FLRT3 may have a crucial role in regulating cellular adhesion between the epithelial apical ridge and the underlying mesenchyme and in establishing the dorso-ventral position of the ridge.

Animals↗

PubMed2005

Expression of csal1 in pre limb-bud chick embryos.

The spalt family of transcriptional repressors has been implicated in limb, heart, ear and kidney development and truncating mutations in a human gene, SALL1, result in the autosomal dominant disorder Townes-Brocks syndrome. Here we show the expression pattern of the chick orthologue of the SALL1 gene, csal1, during early development. We found csal1 expression in the heart and in the pharynx, a source of inductive signals during heart development. Expression was also seen in involuting mesoderm and later in presegmented paraxial mesoderm. We also describe expression in the ectoderm and neural plate of the early embryo and subsequent expression in the neural tube.

Animals↗