Dual influence of the yeast Cat1p (Snf1p) protein kinase on carbon source-dependent transcriptional activation of gluconeogenic genes by the regulatory gene CAT8

Nucleic Acids Res. 1996 Jun 15;24(12):2331-7. doi: 10.1093/nar/24.12.2331.

Abstract

The CSRE (carbon source-responsive element) is a sequence motif responsible for the transcriptional activation of gluconeogenic structural genes in Saccharomyces cerevisiae. We have isolated a regulatory gene, DIL1 (derepression of isocitrate lyase, = CAT8), which is specifically required for derepression of CSRE-dependent genes. Expression of CAT8 is carbon source regulated and requires a functional Cat1p (Snf1p) protein kinase. The derepression defect of CAT8 in a cat1 mutant could be suppressed by a mutant Mig1p repressor protein. Derepression of CAT8 also requires a functional HAP2 gene, suggesting a regulatory connection between respiratory and gluconeogenic genes. Carbon source-dependent protein-CSRE complexes detected in a gel retardation analysis with wild-type extracts were absent in cat8 mutant extracts. However, similar experiments with an epitope-tagged CAT8 gene product in the presence of tag-specific antibodies gave evidence against a direct binding of Cat8p to the CSRE. A constitutively expressed GAL4-CAT8 fusion gene revealed a carbon source-dependent transcriptional activation of a UAS(GAL)-containing reporter gene. Activation mediated by Cat8p was no longer detectable in a cat1 mutant. Thus, biosynthetic control of CAT8 as well as transcriptional activation by Cat8p requires a functional Cat1p protein kinase. A model proposing CAT8 as a specific activator of a transcription factor(s) binding to the CSRE is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Carbon / metabolism
  • DNA, Fungal
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Gene Dosage
  • Gene Expression Regulation, Fungal*
  • Gluconeogenesis / genetics*
  • Molecular Sequence Data
  • Mutation
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcriptional Activation

Substances

  • CAT8 protein, S cerevisiae
  • DNA, Fungal
  • Fungal Proteins
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Carbon
  • SNF1-related protein kinases
  • Protein-Serine-Threonine Kinases