The molecular organization of the mouse PEA3 gene

Abstract

PEA3 is a member of the ETS family of genes. It is expressed in the adult mouse brain and epididymis. It is also expressed in the embryonal carcinoma P19 and F9 cell lines, where its expression is reduced following retinoic acid-induced differentiation. Sequencing of two human cDNA clones revealed the existence of alternatively-spliced PEA3 isoforms from the human PEA3 gene. Consequently there is a likelihood that such alternative splicing also occurs within the mouse PEA3 gene. If this is so, it would be of interest to determine the organization of the mouse PEA3 gene. This information will be necessary to explain any alternativelyspliced PEA3 isoforms that might be observed. To obtain this information, 21 kb of mouse genomic DNA containing the mouse PEA3 gene locus was isolated, subcloned and sequenced. This sequence data revealed that the mouse PEA3 messenger RNA (as present in several previously-characterized cDNAs) is encoded by 13 exons distributed over 14 kb of the mouse genome. To ensure that the complete PEA3 mRNA had been obtained and characterized, the 5' end of the PEA3 mRNA was isolated by the RACE protocol (Rapid Amplification of cDNA Ends). The results of this analysis indicated a transcription start site corresponding to the start of exon 1. The region immediately upstream of this likely initiation site contains numerous cognate sites for transcription factors which may play a role in controlling PEA3 transcription.