TY - JOUR
T1 - Transcriptional control by galactose of a yeast gene encoding a protein homologous to mammalian aldo/keto reductases
AU - Magdolen, Viktor
AU - Oechsner, Ulrich
AU - Trommler, Paul
AU - Bandlow, Wolfhard
PY - 1990/5/31
Y1 - 1990/5/31
N2 - Expression of the S. cerevisiae gene, GCY, encoding a 35-kDa protein with striking homology to mammalian aldo/keto reductases, is under the control of galactose: the intracellular concentration of the respective mRNA (about 1300 nt in length) varies strongly with the carbon source. It is particularly high when galactose is the sole energy source but is low as soon as glucose is present. Lactate, glycerol and raffinose lead to intermediate expression. Both Northern blot analyses and lacZ fusion data indicate a 20- to 50-fold increase in the steady state concentrations of mRNA and βGal activity, respectively, when grown on galactose as compared to glucose. The gene is depressed aftercultivation on glycerol in the wt and in a gal80 mutant background but remains uninducible by galactose in strains carrying either a gal2 or a gal4 mutation, affecting galactose permease and the GAL gene trans-activator, respectively. Analysis of GCY expression in gal regulatory mutants reveals epistasis interactions of the gal4 and the gal80 mutations as expected if GCY is regulated by the Gal control system. Repression of GCY transcription by glucose is observed in all three above gal mutant strains. The results suggest that the gene is both positively controlled by galactose and negatively by glucose. Analysis of a set of upstream deletions identifies a single UAS matching the consensus for GAL gene upstream regulation sites. By contrast to other genes regulated by galactose, disruption mutants of GCY exhibit no obvious phenotype, and in particular do not lose the ability to grow on and adapt to galactose. Enzyme tests with AKR-specific substrates suggest that GCY encodes a carbonyl reductase.
AB - Expression of the S. cerevisiae gene, GCY, encoding a 35-kDa protein with striking homology to mammalian aldo/keto reductases, is under the control of galactose: the intracellular concentration of the respective mRNA (about 1300 nt in length) varies strongly with the carbon source. It is particularly high when galactose is the sole energy source but is low as soon as glucose is present. Lactate, glycerol and raffinose lead to intermediate expression. Both Northern blot analyses and lacZ fusion data indicate a 20- to 50-fold increase in the steady state concentrations of mRNA and βGal activity, respectively, when grown on galactose as compared to glucose. The gene is depressed aftercultivation on glycerol in the wt and in a gal80 mutant background but remains uninducible by galactose in strains carrying either a gal2 or a gal4 mutation, affecting galactose permease and the GAL gene trans-activator, respectively. Analysis of GCY expression in gal regulatory mutants reveals epistasis interactions of the gal4 and the gal80 mutations as expected if GCY is regulated by the Gal control system. Repression of GCY transcription by glucose is observed in all three above gal mutant strains. The results suggest that the gene is both positively controlled by galactose and negatively by glucose. Analysis of a set of upstream deletions identifies a single UAS matching the consensus for GAL gene upstream regulation sites. By contrast to other genes regulated by galactose, disruption mutants of GCY exhibit no obvious phenotype, and in particular do not lose the ability to grow on and adapt to galactose. Enzyme tests with AKR-specific substrates suggest that GCY encodes a carbonyl reductase.
KW - Recombinant DNA
KW - Saccharomyces cerevisiae
KW - galactose regulation
KW - glucose repression
KW - lacZ fusions
KW - ρ{variant}-crystallin
UR - http://www.scopus.com/inward/record.url?scp=0025334921&partnerID=8YFLogxK
U2 - 10.1016/0378-1119(90)90445-W
DO - 10.1016/0378-1119(90)90445-W
M3 - Article
C2 - 2199324
AN - SCOPUS:0025334921
SN - 0378-1119
VL - 90
SP - 105
EP - 114
JO - Gene
JF - Gene
IS - 1
ER -