Expression of TGFβ1/β3 during early chick embryo development

Abstract

We have used an antibody against a TGF beta peptide fragment to localize this growth factor in the early chick embryo from laying to the ten-somite stage of development. Western blotting showed that the antibody reacted with both mammalian TGF beta 1 and chicken TGF beta 3. By immunocytochemistry we find that at the earliest developmental stage (stage X of Eyal-Giladi and Kochav) immunoreactivity to this antibody is primarily located in the cells of the area opaca and marginal zone, as well as in the most peripheral edge cells of the blastoderm. The yolk is non-reactive, except in a highly localized region subjacent to the edge cells. This pattern persists at stage XII, and at both stages individual isolated cells in the epiblast and hypoblast are also reactive. By the time of gastrulation, reactivity in the epiblast is polarized to the ventral extremity of the cells, and again some isolated cells in this layer are intensely immunoreactive. At this stage also, the endoderm cells, particularly those underlying the primitive streak, are positive, as are the mesoderm cells lateral to the streak. At somite stages, the neuroepithelium is not reactive but the ectoderm lateral to it is strongly positive. At the caudal primitive streak levels of early somite embryos, the ectoderm and endoderm are immunoreactive while the mesoderm loses the reactivity it showed at the early gastrulation stages. The neuroepithelial cells later show reactivity at their apical poles, and, as at the earlier stages, individual cells show intense labelling. These results indicate that TGF beta 1 and/or TGF beta 3 immunoreactivity is developmentally regulated from very early stages of morphogenesis in the chick, and together with data from earlier functional studies, suggest that this factor has roles in embryonic axis formation and in blastoderm expansion.

Regulation of Avian Cardiac Myogenesis by Activin/TGFβ and Bone Morphogenetic Proteins

“…The ability of activin to instructively induce cardiac myogenesis in epiblast, but not in mesoderm derived from epiblast, mimics the activity of pregastrula hypoblast (Yatskievych et al, 1997) and is consistent with the localization of activin ␤ mRNAs to the chick pregastrula hypoblast (Mitrani et al, 1990). TGF␤ proteins have been detected in scattered cells of the hypoblast and in marginal zone cells of the pregastrula chick embryo (Sanders et al, 1994), and TGF␤-1 can likewise substitute for the hypoblast to induce cardiac myogenesis in epiblast. Activin and TGF␤ also have similar mesoderm-inducing activities in amphibian assays (Rosa et al, 1988;Green et al, 1992;Logan and Mohun, 1993) and act through common intracellular transducers, the Mad proteins.…”

“…TGF␤ proteins can induce dorsal mesoderm from Xenopus animal caps (Rosa et al, 1988). Since TGF␤ proteins are present within some cells of the pregastrula hypoblast (Sanders et al, 1994), the ability of TGF␤-1 to substitute for hypoblast to induce cardiac myogenesis within chick posterior epiblast was also tested. Like activin, TGF␤-1 induced the appearance of cardiac myocytes in responsive epiblast in a dose-dependent manner (Fig.…”

“…High concentrations of activin can also induce cardiac myogenesis in the amphibian animal cap assay (Logan and Mohun, 1993). TGF␤ proteins have been detected in the marginal zone region of the chick pregastrula embryo and in some cells of the hypoblast (Sanders et al, 1993(Sanders et al, , 1994. Although TGF␤ have been shown to induce some mesodermal cell types in amphibian animal caps (Rosa et al, 1988), the potential role of TGF␤ molecules in early steps of cardiac myogenesis in amniotes has not been examined.…”

Mechanisms involved in valvuloseptal endocardial cushion formation in early cardiogenesis: Roles of transforming growth factor (TGF)-β and bone morphogenetic protein (BMP)

“…Only a few reports dealing with the spatiotemporal expression of TGFβs during chick embryogenesis have been published despite the large number of morphogenetic and experimental investigations of avian embryogenesis (Boyer et al, 1999b; Choy et al, 1991; Jakowlew et al, 1994; Potts et al, 1992; Sanders et al, 1994; Yamagishi et al, 1999b). During chick cardiogenesis, TGFβ3 mRNA is expressed in the primitive heart tube at stage 8–9 (just before spontaneous beating begins).…”

Expression of TGFβ3 RNA during chick embryogenesis: a possible important role in cardiovascular development

“…TGFβ3-null mice show defective morphogenesis of palate and lung (Kaartinen et al 1995;Proetzel et al 1995). Only a few reports dealing with the spatiotemporal expression of TGFβs during chicken embryogenesis have been published, despite the large number of morphogenetic and experimental investigations of avian embryogenesis (Choy et al 1991;Potts et al 1991Potts et al , 1992Jakowlew et al 1994;Sanders et al 1994). We and others have reported that TGFβ3 plays a critical role in the formation of chick endocardial cushion tissue (Potts et al 1992;Nakajima et al 1998).…”