[Expression of a gene for hybrid protein containing the [Val8] amino acid sequence of calcitonin in yeast cells].

A recombinant plasmid has been constructed, which directs the synthesis of a hybrid protein, yeast repressible acid phosphatase [Val8]calcitonin, in yeast. The plasmid contains a truncated gene (pho5) acid phosphatase lacking 96 C-terminal amino acids replaced by the synthetic gene for human calcitonin and sequences required for the plasmid propagation in transformed yeast cells. A modified RIA method using immobilisation of protein extracts on solid supports was developed to monitor the expression of the hybrid protein. By use of this method, as well as by standard RIA of CNBr-cleaved protein extracts, synthesis of a calcitonin-related protein was detected in extracts of transformed strains grown under conditions inducing pho5 promoter.