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  • Prof.  Abraham Fainsod
Prof. Abraham Fainsod
Early embryogenesis in vertebrates is characterized initially by the generation of a pluripotent cell population (i.e. embryonic stem cells) that will serve as the source of material to form the embryonic tissues. During gastrulation numerous events will take place in parallel, which will result in the establishment and organization of the body, making it one of the earliest and crucial steps during embryonic development in vertebrates. At the onset of gastrulation, the pluripotent cells generated during previous cleavage stages are induced to differentiate into the three germ layers, ectoderm, mesoderm and endoderm. While the ectoderm will remain outside and eventually cover the embryo (epidermis) and give rise to the central nervous system, the prospective mesoderm and endoderm will invaginate and populate the embryo from within. The mesoderm will give rise to numerous tissues including muscle, kidney, blood, while the endoderm will provide the internal lining of the alimentary tube, the liver and the pancreas among others.
In the frog, Xenopus laevis, gastrulation starts with the formation of the dorsal blastopore lip through which a coherent sheet of cells begins to invaginate to form endoderm and mesoderm. Since the classical experiments of Spemann and Mangold it has been shown that the dorsal lip tissue is a specialized structure in the early embryo and can function as a potent inducer of ectopic embryonic axes when transplanted onto the ventral side of a recipient embryo. This structure, termed Spemann's organizer, performs numerous functions, among them neural induction within the ectoderm and dorsalization of the mesendoderm. As a result of organizer function, the fate of host cells surrounding the grafted tissue is influenced in a non-cell autonomous fashion, through the action of secreted factors, to become dorsal mesoderm and neural tissue.
We are interested in the genetic pathway(s) involved in the regulation of the onset of gastrulation, the formation of Spemann's organizer and the subsequent patterning of the embryo along the dorsal-ventral and anterior-posterior axis. We are at present studying different aspects of axis formation in vertebrate embryos. We are particularly interested in the regulation of the onset of gastrulation and the end of the pluripotent state in the embryo, the regulation of the formation of Spemann's organizer and further elucidation of the dorsal and ventral pathways in the Xenopus embryo. We continue our studies on the early anterior-posterior and dorsal-ventral patterning of the embryo and the role of the Cdx genes and the BMP pathway and their interactions with other signaling pathways known to function along these axes. As part of our interest on the early anterior-posterior axis we have also established an experimental model to study the embryonic malformations characteristic of Fetal Alcohol Spectrum Disorder and in particular its strongest manifestation, Fetal Alcohol Syndrome.
Research Projects
The Cdx genes as early regulators of embryonic development
The regulation of gastrulation
Establishment of the dorsal-ventral axis of the embryo
Genetic Predisposition to Fetal Alcohol Syndrome
Molecular Regulation of Intrauterine/Fetal Growth Restriction
Scaling the Dorsal-Ventral Gradient with Embryo Size


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