Molecular analysis of the human class I alcohol dehydrogenase gene family and nucleotide sequence of the gene encoding the beta subunit.

G Duester,M Smith,V Bilanchone,G W Hatfield

doi:10.1016/s0021-9258(17)35892-1

Abstract

Human alcohol dehydrogenase (ADH) exists as a heterogeneous group of isozymes capable of oxidizing a wide variety of aliphatic and aromatic alcohols. The five distinct human ADH subunits, each encoded by a separate gene, are differentially expressed during development and are subject to tissue-specific regulation. To analyze the organization and regulation of human ADH genes we first isolated a cDNA clone (pADH12) encoding the 3' portion of the beta ADH gene. In the current study pADH12 was used to screen a human genomic library, and several overlapping and nonoverlapping clones were selected. Hybridization and partial nucleotide sequence analyses of the clones indicated that three full-length human ADH genes encoding the alpha, beta, and gamma subunits were isolated. Human genomic DNA hybridization results indicate that the alpha, beta, and gamma ADH genes form a closely related gene family and suggest that the other known human ADH genes (i.e. those encoding the pi and chi subunits) share a more distant evolutionary relationship. Nucleotide sequence analysis of the beta ADH gene reveals that the coding region is interrupted by eight introns and spans approximately 15 kilobases. A presumptive transcription initiation site for the beta ADH gene was located by S1 nuclease mapping at a position 70 base pairs upstream of the start codon. The 5' flanking region possesses a TATA box promoter element as well as two tandem DNA sequences which display homology to previously examined glucocorticoid-responsive elements.

Highlights

Molecular Analysis of the Human Class I Alcohol Dehydrogenase Gene Family and Nucleotide Sequence of the Gene Encoding the,8 Subunit*
Hybridization and partial nucleotide sequence analyses of the clones indicated that threefull-length human alcohol dehydrogenase (ADH) genes encodingthe a, 6, and y subunitswere isolated
Human genomic DNA hybridization results indicattehat thea, 6, and y ADH genes forma closely related genefamily and suggest that the otherknown human ADH genes (i.e.those encoding the r and x subunits) share a more various ADH isozymescan oxidize a wide variety of aliphatic and aromatic alcohols [18].For many isozymes it has been determined that long-chain aliphatic and aromatic alcohols are better substrates than ethanol, suggesting that ADH is involved in the metabolism of a wide variety of alcohols in the liver [19]

Summary

To analyze the organization and regulationof human

Encoding the 3‘ portion of the 6 ADH gene. In the current study pADH12 was used. to screen a human genomic library, and several overlapping and nonoverlapping clones were selected. Hybridization and partial nucleotide sequence analyses of the clones indicated that threefull-length human ADH genes encodingthe a, 6, and y subunitswere isolated. DNA sequences which display homology to previously Allelic variants at both the ADH2 and ADH3 loci encode examined glucocorticoid-responsive elements. (32), y1 ADH [33], and cy ADH [34] indicate a veryclose relationship between all three, i.e. about 95% identity This ‘The abbreviatisns used are: ADH, alcohol dehydrogenase; kb, kilobase(s); bp, base pair(s); PIPES, 1,4-piperazinediethanesulfonic structural information coupled with the availability of a cDNA for human p ADH [35] has enabled us to initiate an acid; GRE, glucocorticoid responsive elements. In-depth molecular analysis of the Class I ADH gene family

Characterization of Human Alcohol Dehydrogenase Genes

TTT ATGCT

Alu I

CAAT box

Findings

CTT GTGCGTAT