1. 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.
- Author
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Banno S, Noguchi R, Yamashita K, Fukumori F, Kimura M, Yamaguchi I, and Fujimura M
- Subjects
- Amino Acid Motifs genetics, Amino Acid Sequence, Amino Acid Substitution genetics, Aminoimidazole Carboxamide analogs & derivatives, Aminoimidazole Carboxamide pharmacology, Aspartic Acid genetics, Fungal Proteins genetics, Fungicides, Industrial pharmacology, Histidine genetics, Histidine Kinase, Hydantoins pharmacology, Mitogen-Activated Protein Kinases genetics, Molecular Sequence Data, Neurospora crassa drug effects, Neurospora crassa genetics, Neurospora crassa growth & development, Oxidative Stress drug effects, Oxidative Stress genetics, Point Mutation, Protein Kinases genetics, Signal Transduction drug effects, Signal Transduction genetics, Aspartic Acid physiology, Fungal Proteins physiology, Histidine physiology, Mitogen-Activated Protein Kinases physiology, Neurospora crassa physiology, Osmotic Pressure drug effects, Oxidative Stress physiology, Signal Transduction physiology
- Abstract
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.
- Published
- 2007
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