Molecular analysis of the alcohol dehydrogenase (Adhl) gene of maize

Abstract

A cDNA clone of maize Adhl which contains the entire protein coding region of the gene has been constructed. The protein sequence predicted from the nucieotide sequence is in agreement with limited protein sequencing data for the ADH1 enzyme. An 11.5 kb genomic fragment containing the Adhl gene has been isolated using the cDNA clone as a probe, and the gene region fully sequenced. The gene is interrupted by 9 introns, their junction sequences fitting the animal gene consensus sequence. Within the gene there 1s a triplication of a segment (104 bp) spanning an intron-exon junction. Presumptive promoter elements have been identified and are similar in nucleotide sequence and location, relative to the start of transcription, to those of other plant and animal genes. No recognizable poly(A ) addition signal is evident. Comparison of the nucleotide sequences of the cDNA (derived from an Adhl-F allele) and genomic (derived from an Adhl-S allele) clones has identified an amino acid difference consistent with the observed difference in electrophoretic mobility of the two enzymes. The maize ADH1 amino acid sequence is 50% homologous to that of horse liver ADH but is only 20% homologous to yeast ADH.