congresos y reuniones científicas
Endothelin-1/endothelin receptor a cell signalling pathway promotes the specification of the neural crest in Xenopus laevis
MARCELA BONANO; CELESTE TRÍBULO; ROBERTO MAYOR; MANUEL J. AYBAR
Hotel Panamericano, Buenos Aires
Congreso; 4th International Meeting of the Latin American Society of Developmental Biology; 2008
Latin American Society of Developmental Biology
The neural crest (NC) is a multipotent cell population that gives rise to a great number of cell and tissues in the vertebrate organisms. In the amphibian Xenopus laevis, it is specified in the ectoderm from the late gastrula stage. At the present, some signals have been identified to be involved in the NC induction and development, but there is much to be understood. In previous work, we showed for the first time that the Endothelin-1/Endothelin Receptor type A (Edn-1/Ednra) cell signaling pathway has an essential role in the early neural crest development. We determined the expression patterns of three components of this pathway: Preproendothelin-1 (Ppet-1), Endothelin Converting Enzyme (ECE-1) and Endothelin Receptor type A (Ednra) by in situ hybridization and RT-PCR. The expression patterns and embryological experiments showed the NC-mesoderm interaction through Edn1 signaling. We determined that Ednra is involved in the control of the cellular fate without intervening in the control of cell proliferation. The main loss- of function approach consisted in the microinyection of a morpholino antisense oligonucleotide against Ednra, that leaded to the reduction of specific NC marker genes, and a blockade in melanocytes and craniofacial NC-derived cartilages formation. We used an animal cap assay to evaluate the ability of Edn1/Ednra signalling to induce neural crest markers in vitro. Our results showed that Ednra overexpression in animal caps is able to produce a limited induction of NC and neural markers. Ednra is a typical protein G-coupled receptor, with seven transmembrane domains. At the present, it is not well understood the intracellular response that occurs when the ligand Endothelin-1 interacts with the membrane receptor. We also assessed the participation of G proteins in the Edn1/Ednra pathway and in the control of neural crest development. We showed that G protein activation using a non-hydrolyzable analogue of GTP, could rescue the effect of the morpholino MO-Ednra restoring the NC gene markers expression.Our results demonstrate that Edn1/Ednra cell signaling pathway is active from the early steps in the development of Xenopus, having attributes that differentiate its function in this species in comparison to other vertebrate model organisms.