MOLECULAR CHARACTERIZATION OF THE ZEBRAFISH PEA3 ETS-DOMAIN TRANSCRIPTION FACTOR

The PEA3 subfamily of ETS-domain proteins play important roles in regu lating transcriptional activation and have been implicated in several tumorigenic processes. Here we describe the identification of a furthe r 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 do main. The DNA binding specificity of zebrafish PEA3 is virtually ident ical to that exhibited by mammalian family members and is autoregulate d by cisacting inhibitory domains. Transcriptional activation by zebra fish PEA3 is potentiated by the ERK MAP kinase and protein kinase A pa thways. During embryogenesis, PEA3 is expressed in complex spatial and temporal patterns in both mesodermal somites and ectodermal tissues i ncluding the brain, dorsal spinal chord and neural crest. Our characte risation of zebrafish PEA3 furthers our understanding of its molecular function and its expression profile suggests a novel role in cell pat terning in the early vertebrate embryo.