SHORTENED PHOSPHOGLYCERATE KINASE PROMOTER

摘要

A shortened PGK promoter of the PGK gene comprising less than 500 base pairs of the proximal end of the 5' region of the PGK gene. The invention also provides for vehicles capable of replication and expression comprising said shortened PGK promoter operably linked to a structural gene and operably linked to a secretion signal linked to a structural gene, and also provides for hosts transformed with the vehicle. In one embodiment of the invention disclosed, the shortened PGK promoter is used with a process for regulating yeast plasmid copy number by two selectable markers, the first marker having normal or high level expression from its promoter, the second marker, leu2-d, having low level expression from its promoter. Expression of a structural gene on this plasmid system can be increased by lowering the level of the second metabolite (leucine) in the growth medium, thereby selecting for an increased copy number of the second selectable marker (leu2-d), and therefore increased plasmid copy number, which in turn increases the number of copies of the structural gene being expressed.