The role of Xrel3 in early development of Xenopus laevis.

Skhirtladze, Olga (2004) The role of Xrel3 in early development of Xenopus laevis. Masters thesis, Memorial University of Newfoundland.

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Abstract

A novel Xenopus gene called Xrel3 has been recently described, which encodes a member of the Rel/NF-κB family of transcriptional activators (Yang et al., 1998; Lake et al., 2001). Xrel3 mRNA is expressed during early cleavage stages, followed by a dramatic decline to undetectable levels at gastrulation. Later in development, messages localize to the prospective forebrain, dorsal mid-hindbrain, notochord, and otocyst. Overexpression of Xrel3 by microinjecting synthetic RNA into two-cell stage embryo in the animal pole region causes embryos to develop abnormal growths, or tumours (Yang et al., 1998). Ectopic expression of Xrel3 seems to have a major effect on pre-gastrula development. Overexpressed in the dorsal region of the embryo it caused a reduction in dorsoanterior structures in embryos, with a majority of embryos having small heads, kinked backs and shortened tails. Most of them failed to initiate gastrulation movements, as compared to controls. When animal caps from embryos injected with Xrel3 were treated with XTC-CM, Xrel3 reduces activin-induced elongation of animal caps. Xrel3, however, does not reduce FGf-mediated induction of animal caps, or the expression of Xbra in FGF-treated embryos. The results presented here show that Xrel3 inhibits mesoderm induction, but not by interfering with bFGF pathway, but by regulating activin A signalling.

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