Synthesis of a human insulin gene. V. Enzymatic assembly, cloning and characterization of the human proinsulin DNA.

To form a 258-bp sequence coding for human proinsulin, 41 synthetic deoxyribo-oligonucleotide fragments of 11 to 15 nucleotides in length were assembled by enzymatic methods. The coding sequence is preceded by ATG and following by TGA for translation start and stop signals, and terminated in an EcoRI and a BamHI recognition sequence. The complete synthetic sequence was ligated to a plasmid and cloned in Escherichia coli. The cloned DNA was shown to have the correct human proinsulin coding sequence.