cDNA cloning and induction of the alcohol dehydrogenase gene (Adh1) of maize

cDNA clones of Adh1, one of two genes encoding alcohol dehydrogenase (ADH; alcohol:NAD(+) oxidoreductase, EC 1.1.1.1) in the maize genome, have been isolated. They were derived from mRNA extracted from anaerobically treated roots of maize seedlings. Identification was initially made on the basis of molecular weight and electrophoretic properties of the in vitro polypeptide obtained in hybridization-release-translation experiments. The identification was confirmed by antibody precipitation and by the use of maize stocks having different genetic constitutions at the Adh1 locus. The sequence of the longest cDNA segment, approximately 900 base pairs, was determined and appears to code for 168 COOH-terminal amino acids and to have a 3' nontranslated region of 364 base pairs. Reverse Southern hybridizations established that two different Adh1-S stocks produce a mRNA of 1,650 nucleotides, whereas an additional mRNA of 1,750 nucleotides is produced in three Adh1-F stocks. A 50-fold increase in Adh1 mRNA level occurs during anaerobiosis, reaching a maximum at 5 hr. Return to aerobic conditions indicates a half-life of more than 18 hr for the anaerobically induced Adh1 mRNA.