cDNA clones coding for the β‐subunit of human liver alcohol dehydrogenase have differently sized 3'‐non‐coding regions

Three different size classes of cDNA clones coding for the beta 1-subunit of human alcohol dehydrogenase (ADH) were characterized from a human liver cDNA library. Clones were identified by hybridization with synthetic oligodeoxyribonucleotides. A total of 2530 nucleotides were determined, covering an ADH-coding region of 1122 nucleotides, a preceding 72-nucleotide segment and 3 types of 3'-non-coding region. The coding nucleotide sequence is in full agreement with the amino acid sequence of the beta 1-subunit. Of 8 clones identified, 6 had a short, 213-nucleotide 3'-non-coding region; 1 an intermediate, 590-nucleotide 3'-region; and 1 a long, 1330-nucleotide 3'-region. In addition, 2 unused polyadenylation signals were found. These results suggest that human liver beta-ADH mRNAs occur in several size classes, and that in addition to the consensus sequence AATAAA further signals are important for 3'-end formation.