Transcriptional regulation of nonfermentable carbon utilization in budding yeast

Abstract

Saccharomyces cerevisiae preferentially uses glucose as a carbon source, but following its depletion, it can utilize a wide variety of other carbons including nonfermentable compounds such as ethanol. A shift to a nonfermentable carbon source results in massive reprogramming of gene expression including genes involved in gluconeogenesis, the glyoxylate cycle, and the tricarboxylic acid cycle. This review is aimed at describing the recent progress made toward understanding the mechanism of transcriptional regulation of genes responsible for utilization of nonfermentable carbon sources. A central player for the use of nonfermentable carbons is the Snf1 kinase, which becomes activated under low glucose levels. Snf1 phosphorylates various targets including the transcriptional repressor Mig1, resulting in its inactivation allowing derepression of gene expression. For example, the expression of CAT8, encoding a member of the zinc cluster family of transcriptional regulators, is then no longer repressed by Mig1. Cat8 becomes activated through phosphorylation by Snf1, allowing upregulation of the zinc cluster gene SIP4. These regulators control the expression of various genes including those involved in gluconeogenesis. Recent data show that another zinc cluster protein, Rds2, plays a key role in regulating genes involved in gluconeogenesis and the glyoxylate pathway. Finally, the role of additional regulators such as Adr1, Ert1, Oaf1, and Pip2 is also discussed.

Functional and Regulatory Profiling of Energy Metabolism in Fission Yeast

“…Php3 is a component of the CCAATbinding complex, which regulates the glucose-repressible fbp1 gene in S. pombe [66]. Accordingly, the orthologous complex in budding yeast (Hap2-5) acts as the main activator of respiratory genes [4]. The Reb1 transcription factor [54] was also required for respiratory growth, consistent with findings that it functions as an activator of nuclear-encoded respiratory genes (M. R.-L., unpublished data).…”

“…The budding yeast, Saccharomyces cerevisiae, has served as a valuable model system to study the genetic and regulatory basis of energy metabolism at a genome-wide scale [4,5,7,8,[15][16][17][18]. The fission yeast, Schizosaccharomyces pombe, is only remotely related to budding yeast and shows features that promise valuable complementary insights into energy metabolism.…”

Genetic and Functional Investigation of Zn2Cys6Transcription Factors RSE2 and RSE3 in Podospora anserina

“…Glycolysis and gluconeogenesis are two opposite pathways for glucose metabolism (degradation or biosynthesis of glucose), and the fungi have to adapt their carbon metabolism according to the available carbon source. This adaptation occurs through various mechanisms, including the reprogramming of gene expression (3)(4)(5)(6).…”

Maf1, repressor of tRNA transcription, is involved in the control of gluconeogenetic genes in Saccharomyces cerevisiae

“…According to microarray analysis, level of FBP1 mRNA (encoding fructose-1,6-bisphosphatase) was decreased over 6.5 fold and level of PCK1 mRNA (coding for phosphoenolpyruvate carboxykinase) was decreased 2.5 fold in maf1Δ. Both, FBP1 and PCK1, are among multiple genes in S. cerevisiae known to be regulated in a carbon source-dependent manner (Roberts and Hudson, 2006;Schüller, 2003;Turcotte et al, 2010). Consistently with published data (Mercado et al, 1994), in a wild-type yeast strain expression of FBP1 and PCK1 was completely repressed when cells were grown in glucose-rich medium but was significantly higher when the cells were grown in a medium with glycerol as shown by Northern blot analysis (Fig.…”