EXPRESSION OF A SYNTHETIC PROTEIN-BASED POLYMER (ELASTOMER) GENE IN ASPERGILLUS-NIDULANS

A gene for a synthetic protein-based polymer, G-(VPGVG)(119)-VPGV, cod ing for the EG-120mer (elastomer), was cloned into a fungal expression vector to allow constitutive expression of the polymer controlled by the gpdA (glyceraldehyde-3-phosphate dehydrogenase) promoter sequence of Aspergillus nidulans. Stable transformants of A. nidulans showed pl asmid integration with varying copy number when analyzed by Southern-b lot hybridization. Expression of the synthetic gene was demonstrated b y Northern-blot hybridization. However, the translational efficiency f or production of the polymer polypeptide was low, presumably because o f certain codons in the polymer gene (CCG and GUA) that are rarely use d by A. nidulans. Partial purification by reversible phase transition followed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed the presence of polymer protein in a transformant that contai ned multiple copies of the polymer gene. This study represents the fir st attempt to express a synthetic gene with no natural analogy in a fu ngus.