A retroviral repetitive element confers tissue-specificity to the human alcohol dehydrogenase 1C (ADH1C) gene.
The human ADH1A, ADH1B, and ADH1C genes encode alcohol dehydrogenases (ADHs) that metabolize ethanol. They evolved by recent tandem duplications and have similar proximal cis-acting elements, but differ in tissue-specificity. We hypothesized that distal cis-acting elements confer tissue-specificity. In this article, we identify multiple cis-acting elements in the ADH1C upstream region. Negative elements in the fragments from bp -1,078 to -622 and from bp -3,957 to -2,651 decreased transcription activity to 41 and 14%, respectively. A tissue-specific regulatory element in the region between bp -1,503 and -1,053 stimulated transcription sixfold in H4IIE-C3 hepatoma cells but reduced transcription to 23% in HeLa cells. This regulatory element was mapped to a repetitive sequence that is similar to the U3 repeat within the long terminal repeat of human endogenous retrovirus ERV9. The 30-fold difference in expression between two cell lines demonstrates that this upstream U3 element, which inserted after the duplications that created the three class I ADH genes, plays an important role in regulating tissue-specificity of ADH1C. The ubiquitous Nuclear factor-Y (NF-Y) and an H4IIE-C3/liver-specific factor bound to the subrepeat sequence. This result suggested that tissue specificity might result from combinatorial regulation by these two transcription factors.
Chen
Hui-Ju
HJ
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5122, USA.
Carr
Kristie
K
Jerome
Ronald E
RE
Edenberg
Howard J
HJ
D000426:Alcohol Dehydrogenase / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D023081:CCAAT-Binding Factor / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics; D018983:DNA Footprinting; D003850:Deoxyribonuclease I; D015971:Gene Expression Regulation, Enzymologic; D005809:Genes, Regulator; D006367:HeLa Cells; D006801:Humans; D009928:Organ Specificity / Q000235:genetics*; D051381:Rats; D012190:Retroviridae / Q000235:genetics; D020079:Terminal Repeat Sequences / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism
D023081:CCAAT-Binding Factor; D014157:Transcription Factors; C402244:nuclear factor Y; D000426:Alcohol Dehydrogenase; D003850:Deoxyribonuclease I