Isolation and characterisation of a cDNA encoding the precursor for human apolipoprotein A-II

cDNA clones encoding human apolipoprotein AII have been isolated from an adult liver cDNA library. Apo AII mRNA was shown to be approximately 600 bases in length by RNa blot hybridisation. The intracellular precursor of apo AII inferred from the cDNA sequence to be a 100 amino acid polypeptide consisting of the 77 residue mature protein and an additional 23 amino terminal residues. The amino terminal extension, divisible into an 18 residue signal peptide and a 5 residue propeptide, is separated from the first amino acid of mature apo AII by dibasic residues. The 5' untranslated region of the message is 61 bases in length and the 3' untranslated region 113 bases. A polyadenylation signal is situated 14 bases 3' of the poly(A) tall.