The human
alcohol dehydrogenase gene ADH2 is expressed at high levels in liver, at lower levels in kidney and several other tissues, and is not expressed in other tissues such as spleen. This pattern of expression suggests a complex regulatory region that responds to a variety of
transcription factors in different cellular contexts. Seven cis-acting sequences in the proximal 271 bp of the ADH2 promoter were mapped. The occupancy of these sites differed markedly among extracts from liver, kidney, spleen, H4IIE-C3 cells, HeLa cells, and
CV-1 cells. These differences in occupancy were accompanied by differences in gene expression in the three cell lines. The ADH2 promoter directed substantial CAT expression in H4IIE-C3 cells (rat
hepatoma) and in HeLa cells, but only minimal expression in
CV-1 cells (monkey kidney fibroblasts). The three cell lines differed in the effects of deletions within the promoter. An ADH2 promoter that contained both the USF/MLTF site and the G3T site gave four- to eight-fold higher expression in both H4IIE-C3 and HeLa cells than a smaller promoter that lacked these sites; in contrast, these sequences did not significantly stimulate transcription in
CV-1 cells. A CTF/NF-I-related site acted as a negative
element in all three cell lines. Coexpression of
C/EBP alpha altered the cell specificity. The ADH2 promoter was moderately stimulated (two-fold) by coexpression of
C/EBP alpha in H4IIE-C3 cells, but markedly stimulated in HeLa cells and in
CV-1 cells (11- and 20-fold, respectively). These results demonstrate the differential importance of cis-acting sequences and of specific
transcription factors in different cells, which allows regulated expression of ADH2 in multiple tissues.