Expression inEscherichia coli K12 strains of two synthetic human calcitonin genes differing in codon composition

Two genes coding for a Val⁸-variant of the human calcitonin (hCT) are synthesized on two different codon biases: the native codons for the hCT gene and the codons preferential forEscherichia coli. Both genes are fused to a synthetic human interferon-gamma (IF) gene [6] and expressed in various strains ofE. coli K12. It is found that, in all host strains used, the level of expression of both genes is similar and much lower (1/50–1/100) than that of the IF gene alone.