A UNIQUE AROMATASE (P-450AROM) MESSENGER-RNA FORMED BY ALTERNATIVE USE OF TISSUE-SPECIFIC EXONS-1 IN HUMAN SKIN FIBROBLASTS

Aromatase mRNA in human skin fibroblasts was greatly increased in the presence of dexamethasone. Aromatase cDNA was prepared depending on mRNA of dexamethasone-treated fibroblasts by the PCR method including the rapid amplification of cDNA ends (RACE) protocol. The isolated cDNA had the same sequences as placental aromatase cDNA in the region encoded by exons 2-10. However, all 5'-fragments obtained from fibroblast aromatase cDNA contained a unique sequence in the region encoded by exon 1. A unique sequence was also deduced for the region between exons 1 and 2 of the placental aromatase gene from its cDNA, indicating that this region is used as an exon 1 by alternative splicing in skin fibroblasts. Tissue-specific use of multiple exons 1 in the splicing of aromatase transcripts was demonstrated by the mRNAs obtained from various tissues. © 1992.