Our objective is to construct a bacterial strain (a derivative of E. coli K12) that will synthesize insulin. We will isolate mRNA for pre-pro-insulin from a rat insulinoma, make a double-stranded cDNA copy, and clone that DNA in an EK2 system. We shall then isolate, characterize and sequence the pre-pro-insulin structural DNA, and fuse it into a plasimid to a bacterial promoter and ribosome binding site, so as to force translation of a pre-pro-insulin polypeptide.