EXPRESSION OF TESTIS ANGIOTENSIN-CONVERTING ENZYME IS MEDIATED BY A CYCLIC-AMP RESPONSIVE ELEMENT

Testis angiotensin-converting enzyme (testis ACE), an ACE isozyme that plays an important role in male fertility, is transcribed from a uniq ue promoter active only in developing spermatids. In vitro analysis su ggests the importance of a cyclic AMP response element (CRE)-like regi on within the testis ACE promoter, and similar DNA motifs are importan t in the expression of a variety of testis-specific genes. In the pres ent study, we examined the effects of mutations in the CRE-like elemen t on testis ACE promoter activity in vivo using transgenic mice. Disru ption of this element reduced reporter gene expression to near backgro und levels. In contrast, conversion of the CRE-like element to a conse nsus CRE-binding site resulted in high level expression of the reporte r gene specifically in the testis. These experiments prove that the CR E-like element is essential for testis ACE promoter activity, although it does not appear to be responsible for its tissue specificity. Thes e data provide insight into how a phenotypically differentiated tissue , ie, male gem cells, regulate tissue-specific gene expression.