Efficient Expression in Escherichia coli of a Mature and a Modified Human Interferon-β1

ABSTRACT Ten recombinant plasmids were constructed which direct the synthesis of a mature human interferon-β1 (IFN-β1 under the control of the Escherichia coli tryptophan (trp) promoter. The spacing between the Shine-Dalgarno sequence of the trpL and the ATG initiation codon of the interferon gene was varied from 6 to 23 nucleotides by utilizing a Cla I site located within the spacer region of the plasmids. The optimal spacing for expression of IFN-β1 was determined to be 8–13 nucleotides from the results of interferon assay.