Regulation of hypoxic gene expression in yeast

Kidney Int. 1997 Feb;51(2):507-13. doi: 10.1038/ki.1997.71.


Baker's yeast, Saccharomyces cerevisiae, can adapt to growth under severe oxygen limitation. Two regulatory systems are described here that control this adaptation. The first involves a heme-dependent repression mechanism. Cells sense hypoxia through the inability to maintain oxygen-dependent heme biosynthesis. Under aerobic conditions, heme accumulates and serves as an effector for the transcriptional activator Hap1. The heme-Hap1 complex activates transcription of the ROX1 gene that encodes a repressor of one set of hypoxic genes. Under hypoxic conditions, heme levels fall, and a heme-deficient Hap1 complex represses ROX1 expression. As a consequence, the hypoxic genes are derepressed. The second regulatory system activates gene expression in response to a variety of stress conditions, including oxygen limitation. Oxygen sensing in this system is heme-independent. The same DNA sequence mediates transcriptional activation of each stress signal.

MeSH terms

  • Base Sequence
  • Binding Sites
  • Consensus Sequence
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Fungal Proteins / genetics
  • Gene Expression Regulation, Fungal*
  • Genes, Fungal
  • Heme / metabolism
  • Mediator Complex
  • Oxygen / metabolism*
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • DNA, Fungal
  • DNA-Binding Proteins
  • Fungal Proteins
  • Mediator Complex
  • RNA, Fungal
  • RNA, Messenger
  • ROX1 protein, S cerevisiae
  • ROX3 protein, S cerevisiae
  • Repressor Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Heme
  • RNA Polymerase II
  • Oxygen