Schizosaccharomyces pombe gad7+ encodes a phosphoprotein with a bZIP domain, which is required for proper G1 arrest and gene expression under nitrogen starvation

Genes Cells. 1996 Apr;1(4):391-408. doi: 10.1046/j.1365-2443.1996.d01-247.x.


Background: Fission yeast cells arrest at G1 phase when starved of nitrogen. The molecular mechanism that ensures this arrest is poorly understood. We took a genetic approach to this problem.

Results: The fission yeast gad7-1 mutant failed to arrest at G1 when starved of nitrogen, and was poor in mating and sporulation. The gad7 gene was cloned by complementation. The deduced gad7 gene product was a bZIP protein of 566 amino acids, which could bind to the CRE (cAMP response element) sequence in vitro. Disruption of gad7 resulted in the same phenotypes as gad7-1. Expression of ste11, which encodes a key transcription factor for sexual development, was not inducible in the disruptant. Gad7 was co-immunoprecipitated with another bZIP protein Pcr1, suggesting that the two proteins form a heterodimer in vivo. Gad7 was phosphorylated, and the state of its phosphorylation appeared to be modified in pka1delta or wis1delta cells.

Conclusions: Gad7, a CRE-binding protein that cooperates with Pcr1, is required for proper G1 arrest and gene expression under nitrogen starvation. Gad7 is a phosphoprotein, whose activity may be regulated by protein kinases including the cAMP-dependent protein kinase (Pka1) and Wis1 osmosensory MAP kinase kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activating Transcription Factor 1
  • Amino Acid Sequence
  • Base Sequence
  • Basic-Leucine Zipper Transcription Factors
  • Carrier Proteins / genetics
  • Cloning, Molecular
  • Cyclic AMP Response Element-Binding Protein / genetics*
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • DNA, Fungal / analysis
  • DNA-Binding Proteins / genetics*
  • Fungal Proteins / genetics*
  • G-Box Binding Factors
  • G1 Phase / genetics*
  • Gene Expression Regulation, Fungal / genetics*
  • Genomic Library
  • Intracellular Signaling Peptides and Proteins*
  • Mitogen-Activated Protein Kinase Kinases
  • Molecular Sequence Data
  • Mutagenesis
  • Nitrogen
  • Phosphoproteins
  • Phosphorylation
  • Protein Kinases
  • Protein-Serine-Threonine Kinases / genetics
  • Recombinant Fusion Proteins
  • Restriction Mapping
  • Schizosaccharomyces / genetics*
  • Schizosaccharomyces pombe Proteins*
  • Sequence Analysis, DNA
  • Transcription Factors / genetics*


  • Activating Transcription Factor 1
  • Basic-Leucine Zipper Transcription Factors
  • Carrier Proteins
  • Cyclic AMP Response Element-Binding Protein
  • DNA, Fungal
  • DNA-Binding Proteins
  • Fungal Proteins
  • G-Box Binding Factors
  • Intracellular Signaling Peptides and Proteins
  • Phosphoproteins
  • Recombinant Fusion Proteins
  • Schizosaccharomyces pombe Proteins
  • Transcription Factors
  • atf1 protein, S pombe
  • protein kinase modulator
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • Cyclic AMP-Dependent Protein Kinases
  • Mitogen-Activated Protein Kinase Kinases
  • wis1 protein, S pombe
  • Nitrogen

Associated data

  • GENBANK/D63666