Divergence in regulation of the PEA3 family of ETS transcription factors.

Here, we report the cloning of a cDNA encoding zebrafish ER81, a member of the PEA3 family of Ets transcription factors. Strikingly, the spatial and temporal expression of er81 is significantly different from its Xenopus orthologue, XER81, whose expression is more reminiscent of the FGF dependant zebrafish PEA3 family members. In keeping with this observation, while pea3, erm and XER81 require FGF activity for their expression, er81 does not require FGF signalling. Our results suggest that, since the vertebrate specific expansion of the PEA3 subfamily of Ets transcription factors, the regulation of PEA3 genes has been independently modified during the evolution of different vertebrate lineages.