Roles of putative His-to-Asp signaling modules HPT-1 and RRG-2, on viability and sensitivity to osmotic and oxidative stresses in Neurospora crassa

Curr Genet. 2007 Mar;51(3):197-208. doi: 10.1007/s00294-006-0116-8.


Neurospora crassa has a putative histidine phosphotransfer protein (HPT-1) that transfers signals from 11 histidine kinases to two putative response regulators (RRG-1 and RRG-2) in its histidine-to-aspartate phosphorelay system. The hpt-1 gene was successfully disrupted in the os-2 (MAP kinase gene) mutant, but not in the wild-type strain in this study. Crossing the resultant hpt-1; os-2 mutants with the wild-type or os-1 (histidine kinase gene) mutant strains produced no progeny with hpt-1 or os-1; hpt-1 mutation, strongly suggesting that hpt-1 is essential for growth unless downstream OS-2 is inactivated. hpt-1 mutation partially recovered the osmotic sensitivity of os-2 mutants, implying the involvement of yeast Skn7-like RRG-2 in osmoregulation. However, the rrg-2 disruption did not change the osmotic sensitivity of the wild-type strain and the os-2 mutant, suggesting that rrg-2 did not participate in the osmoregulation. Both rrg-2 and os-2 single mutation slightly increased sensitivity to t-butyl hydroperoxide, and rrg-2 and hpt-1 mutations increased the os-2 mutant's sensitivity. Although OS-1 is considered as a positive regulator of OS-2 MAP kinase, our results suggested that HPT-1 negatively regulated downstream MAP kinase cascade, and that OS-2 and RRG-2 probably participate independently in the oxidative stress response in N. crassa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / genetics
  • Amino Acid Sequence
  • Amino Acid Substitution / genetics
  • Aminoimidazole Carboxamide / analogs & derivatives
  • Aminoimidazole Carboxamide / pharmacology
  • Aspartic Acid / genetics
  • Aspartic Acid / physiology*
  • Fungal Proteins / genetics
  • Fungal Proteins / physiology*
  • Fungicides, Industrial / pharmacology
  • Histidine / genetics
  • Histidine / physiology*
  • Histidine Kinase
  • Hydantoins / pharmacology
  • Mitogen-Activated Protein Kinases / genetics
  • Mitogen-Activated Protein Kinases / physiology*
  • Molecular Sequence Data
  • Neurospora crassa / drug effects
  • Neurospora crassa / genetics
  • Neurospora crassa / growth & development
  • Neurospora crassa / physiology*
  • Osmotic Pressure* / drug effects
  • Oxidative Stress / drug effects
  • Oxidative Stress / genetics
  • Oxidative Stress / physiology*
  • Point Mutation
  • Protein Kinases / genetics
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • Signal Transduction / physiology*


  • Fungal Proteins
  • Fungicides, Industrial
  • Hydantoins
  • Aspartic Acid
  • Aminoimidazole Carboxamide
  • Histidine
  • Protein Kinases
  • Mitogen-Activated Protein Kinases
  • os-2 protein, Neurospora crassa
  • Histidine Kinase
  • iprodione