A 27 kDa protein binds to a positive and a negative regulatory sequence in the promoter of the ICL1 gene from Saccharomyces cerevisiae.
IsocitrateICL1, is one of the key enzymes of the glyoxylate pathway, which operates as an anaplerotic route for replenishing the tricarboxylic acid cycle; it is required for growth of Saccharomyces cerevisiae on carbon sources such as ethanol, but is dispensable when fermentable carbon sources are available. The positive regulation of the ICL1 gene by an upstream activating sequence (UAS) element located between -397 and -388 has been previously reported. In this paper we show that the ICL1 promoter sequence 5'-AGTCCGGACTAGCATCCCAG-3' located between -261 and -242 contains an upstream repressing sequence (URS) element. We have identified and partially purified a 27 kDa protein that binds specifically to both the UAS and URS sequences of the ICL1 promoter. For both UAS and URS, binding requires the protein Snf1 (Cat1), a protein kinase essential for the derepression of genes repressed by glucose. Binding does not take place with extracts from glucose-grown strains, unless they lack Mig1, a negative regulatory protein involved in glucose repression.
Ordiz
I
I
Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Biotecnología de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain.
Herrero
P
P
Rodicio
R
R
Gancedo
J M
JM
Moreno
F
F
D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000235:genetics*; D007522:Isocitrate Lyase / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
D005656:Fungal Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C542285:ICL1 protein, S cerevisiae; D007522:Isocitrate Lyase