Molecular characterization of the zebrafish PEA3 ETS-domain transcription factor.

The PEA3 subfamily of ETS-domain proteins play important roles in regulating transcriptional activation and have been implicated in several tumorigenic processes. Here we describe the identification of a further member of this family from zebrafish which most likely represents a homologue of PEA3. A high degree of sequence conservation is observed in the ETS DNA-binding domain and acidic transcriptional activation domain. The DNA binding specificity of zebrafish PEA3 is virtually identical to that exhibited by mammalian family members and is autoregulated by cisacting inhibitory domains. Transcriptional activation by zebrafish PEA3 is potentiated by the ERK MAP kinase and protein kinase A pathways. During embryogenesis, PEA3 is expressed in complex spatial and temporal patterns in both mesodermal somites and ectodermal tissues including the brain, dorsal spinal chord and neural crest. Our characterisation of zebrafish PEA3 furthers our understanding of its molecular function and its expression profile suggests a novel role in cell patterning in the early vertebrate embryo.