Chemical synthesis, cloning and expression of human preproinsulin gene.

A 355 base pair DNA sequence coding for human preproinsulin has been assembled by joining 55 synthetic deoxyoligonucleotide fragments prepared by the modified phosphotriester methodology. Proinsulin was expressed under lac promoter control and truncated β -galactosidase 590 amino acid long sequence. The fused β-galactosidase proinsulin protein was produced in amount to 30 % of the total Escherichia coli proteins. It was also expressed in Μ13 bacteriophage and yeast system.