Effects of growth factors on the commitment of chick blastoderm

Abstract

The fate of the blastoderm in early chick embryos has been established by fate map studies. Cells of the epiblast will constitute the neural tube and the epithelial layer of the embryo, whereas the early mesoderm will contribute to the heart, the lateral mesoderm, the somites and the notochord (Garcia-Martinez et al., 1993). The fate of the endoderm has not been determined so clearly, although it is clear that it will form the endodermal derivatives. A great variety of signaling molecules produced in the blastoderm contribute to the process of determination of the fate of these cells. Among them, there are several growth factors belonging to different families which are strongly produced in discrete regions of the embryo and affect the behaviour of blastodermal cells by activating gene pathways that finally lead to the production of different cell types. Several signaling molecules have been tested and the results have led to important advances in the understanding of early morphogenesis in the chick. It is known that two groups of growth factors are important players in these early steps of patterning and specification in the chick embryo: the fibroblast growth factor family (FGFs) and the bone morphogenetic protein family (BMPs). By delivering FGFs to ectopic places in the blastoderm one is able to change the fate of epithelial cells so that they become neural cells. Here, when heart specific markers were checked, the same growth factors show the ability to initiate and modulate early development of the heart.