cDNA cloning and chromosome assignment of the gene for human brain 14–3–3 protein η chain

Abstract
We present the nucleotide sequence of a cDNA clone of mRNA encoding human 14‐3‐3 protein, a protein kinase‐dependent activator of tyrosine and tryp‐tophan hydroxylases and an endogenous inhibitor of protein kinase C. The 1,730‐nucleotide sequence of the cloned cDNA contains 191 bp of a 5′‐noncoding region, the complete 738 bp of coding region, and 801 bp of a 3′‐noncoding region containing three canonical polyadenylation signals. The 14‐3‐3 protein η chain cDNA encoded a polypeptide of 246 amino acids with a predicted molecular weight 28,196. The predicted amino acid sequence of human 14‐3‐3 protein η was highly homologous to that of previously reported bovine and rat 14‐3‐3 proteins with only two amino acid differences. The sequence carries structural features as putative regions responsible for activation of tyrosine and tryptophan hydroxylases and for inhibition of Ca2+/phospholipid‐dependent protein kinase C. Northern blot analysis demonstrated widespread expression of the 14‐3‐3 protein η chain in cultured cell lines derived from various human tumors. These findings suggest the conservative functions of the 14‐3‐3 protein among species. Spot blot hybridization analysis with flow‐sorted chromosomes it showed that the human 14‐3‐3 protein η chain gene is assigned to chromosome 22.