Stage and tissue‐specific expression of the alcohol dehydrogenase 1 (Adh‐1) gene during mouse development

Abstract
The Adh1 gene product, ADH‐A2, the only known murine class I alcohol dehydrogenase, is able to oxidize retinol (vitamin A) into retinaldehyde, the first enzymatic step in the conversion of retinol into its biologically active metabolite retinoic acid. We have investigated the developmental expression pattern of Adh1 transcripts by in situ hybridization. Transcripts were first detected by embryonic day 10.5 in the mesonephros mesenchyme. During the following gestational days, Adh1 transcripts were detected in several mesenchymal areas, such as nasal, laterocervical, and genital regions. Adh1 transcripts were also detected in a small ectodermal domain at the anterior margins of both forelimbs and hindlimbs. During late fetal development, Adh1 transcripts were found essentially in the epidermis and in a number of tissues which continue to express the gene after birth, such as liver, kidney, gut epithelium, adrenal cortex, testis interstitium, and ovarian stroma. In contrast, a strong expression of Adh1 was found in the mesenchyme of developing lungs, but not in the adult organ. This highly regulated expression of Adh1 is discussed with respect to the local synthesis of retinoic acid during development. Although the promoter of the human counterpart of Adh1 contains a retinoic acid response element (Duester et al. [1991] Mol. Cell. Biol. 11:1638–1646), we report that this element is not conserved in the murine gene. Consistently, Adh1 promoter‐containing reporter constructs were not retinoic acid‐inducible in cotransfections assays with RARs and/or RXRs, suggesting that retinoic acid regulation of Adh1 differs from that of the human gene.