ISOLATION AND CHARACTERIZATION OF ALL-TRANS-RETINOIC ACID-RESPONSIVE GENES IN THE RAT TESTIS

By way of differential screening of testis cDNA libraries from vitamin A-deficient (VAD) rats before and after administration of all-trans r etinoic acid (ATRA), genes, the transcription of which was influenced by ATRA, were isolated. Most clones with an increased transcription en coded different subunits of the same mitochondrial protein complex, cy tochrome c oxidase (COX). The mRNA expression of COX increased by a fa ctor 3.9+/-1.5 (mean+/-SD, n = 4). This increased expression seems to reflect an increased energy demand in the ATRA-supplemented VAD testis . Also, one gene was isolated, the transcription of which was reduced to about 70% by ATRA. This gene, sulfated glycoprotein 2 (Sgp-2), is a major secretion product of Sertoli cells, the function of which is st ill unknown. The effect of ATRA on Sgp-2 expression may be direct, sin ce the promoter of Sgp-2 contains a putative ATRA-responsive element ( RARE). (C) 1998 Wiley-Liss, Inc.