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

Abstract

Three different size classes of cDNA clones coding for the β₁‐rsubunit 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 β₁subunit. 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 β‐ADH mRNAs occur in several size classes, and that in addition to the consensus sequence AATAAA further signals are important for 3'‐end formation.