Genomic organisation and chromosomal localisation of the gene encoding human beta adducin

Adducin (ADD) is a heterodimeric protein of the membrane skeleton with subunits of 103 (α) and 97 kDa (β). It promotes the assembly of the spectrin-actin network. We have previously shown that one point mutation in each of the α and β rat ADD-encoding genes is associated with blood pressure variation in an animal model for hypertension, the Milan hypertensive strain of rats, probably due to a change in the phosphorylation pattern. In fact, the rat mutations, Y to F for α and R to Q for β, are located, respectively, in a tyrosine kinase and a protein kinase A phosphorylation site. We have now determined, for the human β-ADD-encoding gene, its chromosomal localisation, exon-intron organisation and alternative splicing patterns. We report here that human β-ADD is localised on chromosome 2 and we also show a characteristic 3′ end alternative splicing of the β-ADD RNA that generates two distinct β-ADD families, namely ADD 63 and 97; both of them in turn present a very complex differential splicing pattern in the internal exons.