gcr2, a new mutation affecting glycolytic gene expression in Saccharomyces cerevisiae

Screening of a mutagenized strain carrying a multicopy ENO1-'lacZ fusion plasmid revealed a new mutation affecting most glycolytic enzyme activities in a pattern resembling that caused by gcr1: levels in the range of 10% of wild-type levels on glycerol plus lactate but somewhat higher on glucose. The recessive single nuclear gene mutation, named gcr2-1, was unlinked to gcr1, and GCR1 in multiple copies did not restore enzyme levels. GCR2 was obtained by complementation from a YCp50 genomic library; the complemented strain had normal enzyme levels, as did a strain with GCR2 in multiple copies. GCR2 in multiple copies did not suppress gcr1. A chromosomal gcr2 null mutant was constructed; its pattern of enzyme activities resembled that of the gcr2-1 mutant and, like the gcr2-1 mutant, its growth defect on glucose was only partial (in contrast to the glucose negativity of the gcr1 mutant). Northern (RNA) analysis showed that gcr2 and gcr1 affect ENO1 mRNA levels.