Open AccessNew mutations of Saccharomyces cerevisiae that partially relieve both glucose and galactose repression activate the protein kinase Snf1
Author(s) -
Rodríguez Cristina,
Sanz Pascual,
Gancedo Carlos
Publication year - 2003
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2003.tb00141.x
Subject(s) - derepression , biology , saccharomyces cerevisiae , mutant , biochemistry , galactose , snf3 , yeast , galactokinase , kinase , mutation , protein kinase a , gene , psychological repression , escherichia coli , gene expression
We isolated from Saccharomyces cerevisiae two mutants, esc1‐1 and ESC3‐1 , in which genes FBP1 , ICL1 or GDH2 were partially derepressed during growth in glucose or galactose. The isolation was done starting with a triple mutant pyc1 pyc2 mth1 unable to grow in glucose–ammonium medium and selecting for mutants able to grow in the non‐permissive medium. HXT1 and HXT2 which encode glucose transporters were expressed at high glucose concentrations in both esc1‐1 and ESC3‐1 mutants, while derepression of invertase at low glucose concentrations was impaired. REG1 , cloned as a suppressor of ESC3‐1 , was not allelic to ESC3‐1 . Two‐hybrid analysis showed an increased interaction of the protein kinase Snf1 with Snf4 in the ESC3‐1 mutant; this was not due to mutations in SNF1 or SNF4 . ESC3‐1 did not bypass the requirement of Snf1 for derepression. We hypothesize that ESC3‐1 either facilitates activation of Snf1 or interferes with its glucose‐dependent inactivation.