Synthesis of a wheat storage protein subunit in Escherichia coli using novel expression vectors.

Useful plasmid expression vectors have been constructed which allow the synthesis of beta-galactosidase (betaG) fusion polypeptides or of polypeptides specified by cDNA clones in Escherichia coli hosts. A foreign DNA fragment can be inserted in any one of the three reading frames at the unique EcoRI, BamHI or SmaI sites immediately after the initiation codon. The cloned foreign gene is under the control of the lac promoter. Using a cDNA clone that encodes part of a wheat storage protein [a high-Mr (HMW) glutenin subunit] synthesis of a glutenin-beta G fusion protein was demonstrated. Synthesis of the glutenin polypeptide, not fused to beta G, was achieved by replacing the lacZYA genes with a stop codon.