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.
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.
Banno
Shinpei
S
Faculty of Life Sciences, Toyo University, Itakura, Oura-gun, Gunma 374-0193, Japan.
Noguchi
Rieko
R
Yamashita
Kazuhiro
K
Fukumori
Fumiyasu
F
Kimura
Makoto
M
Yamaguchi
Isamu
I
Fujimura
Makoto
M
D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D001224:Aspartic Acid / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D005659:Fungicides, Industrial / Q000494:pharmacology; D006639:Histidine / Q000235:genetics / Q000502:physiology*; D000071677:Histidine Kinase; D006827:Hydantoins / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D009997:Osmotic Pressure / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D017354:Point Mutation; D011494:Protein Kinases / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D005656:Fungal Proteins; D005659:Fungicides, Industrial; D006827:Hydantoins; D001224:Aspartic Acid; D000620:Aminoimidazole Carboxamide; D006639:Histidine; D011494:Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C450461:os-2 protein, Neurospora crassa; D000071677:Histidine Kinase; C033148:iprodione