title: Developmental expression of chick twist and its regulation during limb patterning.
abstract: We have isolated a chick Twist gene (cTwist) and examined its expression pattern during development by whole mount in situ hybridization. In early embryos, cTwist transcripts are found in the developing somites, lateral plate mesoderm, limb mesenchyme, branchial arches and head mesenchyme. At later stages, cTwist expression is found in the sclerotome and dermatome, limb bud mesenchyme, interdigital regions, and distal mesenchyme of the maxillary and mandibular processes. In the developing feathers, cTwist is expressed in the mesenchyme of the buds and becomes restricted to the proximal region of the feather filaments. Additionally, we report that the expression of cTwistin the limb mesenchyme is regulated by the AER, FGFs, RA and SHH. The FGFs secreted by the AER seem to have a critical role in maintaining cTwist expression. SHH is also able to maintain cTwist expression but only in the presence of the AER. Overall, our results provide new evidence that reinforce the existence of an interplay between the cTwist and FGF signalling pathways.
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, Portugal.
authors.forename: A T
authors.initials: AT
authors.lastname: Tavares
authors.forename: J C
authors.initials: JC
authors.lastname: Izpisúja-Belmonte
authors.forename: J
authors.initials: J
authors.lastname: Rodriguez-León
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D019521:Body Patterning / Q000187:drug effects / Q000235:genetics; D002642:Chick Embryo; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005121:Extremities / Q000196:embryology*; D051519:Fibroblast Growth Factor 4; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D053823:Hedgehog Proteins; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000494:pharmacology; D017468:Receptors, Fibroblast Growth Factor / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics*; D014212:Tretinoin / Q000494:pharmacology; D051879:Twist-Related Protein 1
chemical_list: D030161:Avian Proteins; D018076:DNA, Complementary; D051519:Fibroblast Growth Factor 4; D053823:Hedgehog Proteins; D011518:Proto-Oncogene Proteins; D017468:Receptors, Fibroblast Growth Factor; D015534:Trans-Activators; D014157:Transcription Factors; C412362:Twist protein, Gallus gallus; D051879:Twist-Related Protein 1; D051524:Fibroblast Growth Factor 8; D014212:Tretinoin; D005346:Fibroblast Growth Factors