Distinct upstream activation regions for glucose-repressed and derepressed expression of the yeast citrate synthase gene CIT1

Abstract

The yeast CIT1 (mitochondrial citrate synthase) gene is subject to glucose repression and is further repressed by glucose plus glutamate. Based on deletion analysis of a CIT1-lacZ gene fusion, DNA sequences between -548 and -273 are required for full expression of CIT1. The region of transcription initiation and the putative TATA element are located at -150 to -100 and -195 respectively. A restriction fragment containing DNA sequences between -457 and -211 conferred activation and glucose-glutamate regulation when placed in either orientation upstream of a UAS-less heterologous yeast gene. Deletion of DNA sequences between -291 and -273 specifically eliminated derepression of CIT1, and destroyed one of two closely-spaced, potential binding sites for the HAP2,3,4 transcriptional activator protein. Ten-base-pair block substitutions in the region -367 to -348 reduced glucose-repressed expression. Thus, it appears that distinct DNA sequences upstream of CIT1 activate expression in glucose-repressed and derepressed cells. Possible mechanisms of regulation by glutamate plus glucose, are discussed.

A Transcriptional Switch in the Expression of Yeast Tricarboxylic Acid Cycle Genes in Response to a Reduction or Loss of Respiratory Function

“…The CIT1 UAS contains a functional R box. A 10-bp DNA segment of CIT1 from Ϫ367 to Ϫ358 has been shown to be important for glucose-repressed expression of the gene (34,35). Notably, that 10-bp segment starts with GTCAC, an R box binding site for the Rtg1p-Rtg3p heterodimeric complex (14).…”

Controlling promoter strength and regulation in Saccharomyces cerevisiae using synthetic hybrid promoters

“…Our hybrid promoter engineering approach entails combining core promoters with UAS elements to enable fine‐tuned control and amplification of gene expression. Several upstream promoter sequences have previously been identified as transcriptional enhancing elements in S. cerevisiae , including a 240 bp sequence 5′ of the mitotic cyclin CLB2 gene (Van Slyke and Grayhack, 2003), a 275 bp sequence 5′ of the mitochondrial citrate synthase CIT1 gene (Rosenkrantz et al, 1994), and a galactose‐controlled 309 bp sequence 5′ of the GAL1 gene, (West et al, 1984) referred to henceforth as UAS CLB , UAS CIT , and UAS GAL , respectively (Table I). These elements serve as the starting point for this study.…”

Investigation by 13C-NMR and tricarboxylic acid (TCA) deletion mutant analysis of pathways for succinate formation in Saccharomyces cerevisiae during anaerobic fermentation

“…Several genes may be indirectly regulated by the DNA-binding repressor Mig1p, a key protein in the signalling cascade of glucose repression (Klein et al, 1998). CIT1 and CIT3, which encode the mitochondrial citrate synthase (responsible for catalysing the first step in the TCA cycle), and KGD1, KGD2 and LPD1, which encode the oxoglutarate dehydrogenase (OGDH) complex, are activated by Hap4, a transcription factor under the control of Mig1p (de Winde & Grivell, 1993;Rosenkrantz et al, 1994). The expression of CIT1, and other genes encoding enzymes of the TCA pathway [ACO1 and SDH1, 2, 3, 4 encoding the aconitase and succinate dehydrogenase (SDH) complex subunits, respectively], is also controlled by the haem-dependent factors Hap1p and/or Hap2/3/4/5p, the intracellular levels and/or activities of which have been shown to be strongly affected by hypoxia (for a review see Kwast et al, 1998).…”