Analysis of the p450 aromatase gene expression in the Xenopus brain and gonad.

Analysis of 5'-RACE clones revealed two Cyp19 transcript variants (gonad p450 aroms 1 and 2) in the gonads and one Cyp transcript (brain p450 arom) in the brain that differed in their 5'-untranslated region (UTR). Since all cDNAs contained an identical open reading frame, it is considered that while Xenopus aromatase may be encoded by a single Cyp19 gene, it is transcribed by tissue-specific promoters, each of which may be regulated by a distinct set of transcriptional factors. While gonad p450 aroms 1 and 2 and brain p450 arom were expressed in the gonads, brain p450 arom was the predominantly expressed aromatase gene in the brain, with a low expression level of gonad p450 arom 1.