title: Catabolite repression of phosphoenolpyruvate carboxykinase by a zinc finger protein under biotin- and pyruvate carboxylase-deficient conditions in Pichia pastoris.
abstract: We have identified a methanol- and biotin-starvation-inducible zinc finger protein named ROP [repressor of phosphoenolpyruvate carboxykinase (PEPCK)] in the methylotrophic yeast Pichia pastoris. When P. pastoris strain GS115 (wild-type, WT) is cultured in biotin-deficient, glucose-ammonium (Bio(-)) medium, growth is suppressed due to the inhibition of anaplerotic synthesis of oxaloacetate, catalysed by the biotin-dependent enzyme pyruvate carboxylase (PC). Deletion of ROP results in a strain (ΔROP) that can grow under biotin-deficient conditions due to derepression of a biotin- and PC-independent pathway of anaplerotic synthesis of oxaloacetate. Northern analysis as well as microarray expression profiling of RNA isolated from WT and ΔROP strains cultured in Bio(-) medium indicate that expression of the phosphoenolpyruvate carboxykinase gene (PEPCK) is induced in ΔROP during biotin- or PC-deficiency even under glucose-abundant conditions. There is an excellent correlation between PEPCK expression and growth of ΔROP in Bio(-) medium, suggesting that ROP-mediated regulation of PEPCK may have a crucial role in the biotin- and PC-independent growth of the ΔROP strain. To our knowledge, ROP is the first example of a zinc finger transcription factor involved in the catabolite repression of PEPCK in yeast cells cultured under biotin- or PC-deficient and glucose-abundant conditions.
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Nallani
authors.initials: N
authors.lastname: Vijay Kumar
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Pundi N
authors.initials: PN
authors.lastname: Rangarajan
mesh_terms: D001710:Biotin / Q000172:deficiency*; D057465:Catabolite Repression; D003470:Culture Media / Q000737:chemistry; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D046228:Microarray Analysis; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000096:biosynthesis*; D010843:Pichia / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D011766:Pyruvate Carboxylase / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016335:Zinc Fingers
chemical_list: D003470:Culture Media; D012097:Repressor Proteins; D001710:Biotin; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D011766:Pyruvate Carboxylase