Testis

Three Different Promoters Control Expression of the Aromatase Cytochrome P450 Gene (Cyp19) in Mouse Gonads and Brain

Abstract

Aromatase Cytochrome P450, the key enzyme of estrogen biosynthesis is encoded by Cyp19. To elucidate the complex regulation of this gene in mouse gonads (ovary and testis) and brain (thalamic/hypothalamic areas), Cyp19 transcripts were isolated using rapid amplification of cDNA 5' ends and transcript concentrations were estimated in juveniles at different postnatal days (P0, P7, P14) and in adult animals by real- time PCR. In addition, the murine Cyp19 locus including all known exons and promoters was reconstructed from a recently published sequence of a mouse bacterial artificial chromosome. From each of the tissues investigated, Cyp19 transcripts with a specific 5' translated region (5'UTR) were isolated: T_ov from ovary, T_br from brain and T_tes from testis. T_tes included a novel 5'UTR that did not show sequence similarities to other Cyp19 transcripts. Real-time PCR experiments revealed similar levels of Cyp19 transcript concentrations in neonatal gonads of both sexes. The majority of transcripts were T_ov in ovaries and T_tes in testes. During further postnatal development testicular Cyp19 transcript concentrations transiently decreased but the contributions of different transcript variants basically remained unchanged. However, ovarian Cyp19 transcript concentrations increased by about 100 times, and almost 100% of all Cyp19 transcripts were identified as T_ov in adult ovaries. Brains of both sexes showed highest transcript concentrations at P0. However concentrations in female brains were reduced to adult levels earlier than in male brains. In brains of both sexes T_br was found to predominate throughout postnatal life. The results suggest, that the mouse Cyp19 gene includes three different promoters that specifically direct expression in ovary, testis and brain.