Ectopic expression of c-ski disrupts gastrulation and neural patterning inzebrafish

The c-ski proto-oncogene encodes a transcriptional regulator that has been implicated in the development of different tissues at different times durin g vertebrate development. We identified two novel paralogues of the c-ski g ene family, skiA and skiB in zebrafish (Danio rerio). The skiA protein is m aternal and ubiquitous while skiB is zygotic. Overexpression of SkiA or Ski B disrupted gastrulation and resulted in a dorsalized phenotype. In situ an alyses suggested that overexpression of Ski leads to a slight expansion of dorsal-axial mesoderm, diminishment or loss of ventral mesoderm and radiali zation of dorsal neuroectoderm. The dorsalized phenotype could be rescued b y the ventral specifying factor, BMP4. These results provide evidence that Ski proteins participate in dorsal-ventral specification of both neuroectod erm and mesoderm. (C) 2000 Elsevier Science Ireland Ltd All rights reserved .