Regulation of yeast fructose-1,6-bisphosphatase in strains containing multicopy plasmids coding for this enzyme

The structural gene for yeast fructose-1,6-bisphosphatase (FbPase) has been cloned by complementation of a strain carrying the fbp1-1 mutation and lacking FbPase activity. By Northern analysis it could be shown that the fbp1-1 mutation does not interfere with the transcription of the gene although no normal active enzyme is produced. Strains transformed with the cloned gene on a multicopy plasmid overproduce FbPase but are still subject to strong catabolite repression. Catabolite inactivation, however, is slowed down in such strains.