cAMP PARTICIPATION IN Xenopus laevis VITELLOGENIN UPTAKE

Santa Cruz

Congreso; LASDB; 2010

The transformation of oogonia into oocytes is commonly described as oogenesis. In many oviparous vertebrates the growth of oocytes from microscopic to macroscopic dimensions is mainly the result of one of the most exciting examples of cell regulation, named vitellogenesis. This process, general to all oviparous vertebrate species is characterized by hepatic production of the glycoprotein vitellogenin (VTG). VTG is transported via the bloodstream to the ovary where enters the oocytes by a receptor-mediated endocytosis. Previously we demonstrated that in the amphibian Xenopus laevis direct gap junctional communication between oocytes and follicular epithelium is a requirement for endocytic VTG uptake. This suggested that a diffusible signal molecule able to pass through fully open gap junctions could be involved in vitellogenic process.                   In order to determine the identity of the signal molecule, gap junctions coupling/uncoupling experiments with an endocytic tracer were performed. Rescue experiments demonstrated that cAMP is one of the signal molecule involved in vitellogenin uptake during vitellogenesis.