title: Putative homologs of SSK22 MAPKK kinase and PBS2 MAPK kinase of Saccharomyces cerevisiae encoded by os-4 and os-5 genes for osmotic sensitivity and fungicide resistance in Neurospora crassa.
abstract: We cloned and characterized Neurospora NcSSK22 and NcPBS2 genes, similar to yeast SSK22 mitogen-activated protein (MAP) kinase kinase kinase and the PBS2 MAP kinase kinase genes, respectively. Disruptants of the NcSSK22 gene were sensitive to osmotic stress and resistant to iprodione and fludioxonil. Their phenotypes were similar to those of osmotic-sensitive (os) mutants os-1, os-2, os-4, and os-5. The os-4 mutant strain transformed with the wild-type NcSSK22 gene grew on a medium containing 4% NaCl and was sensitive to iprodione and fludioxonil. In contrast, the NcPBS2 gene complemented the osmotic sensitivity and fungicide resistance of the os-5 mutant strain. We sequenced the NcPBS2 gene of the os-5 mutant strain (NM216o) and found five nucleotides deleted within the kinase domain. This result suggests that the gene products of os-4 and os-5 are components of the MAP kinase cascade, which is probably regulated upstream by two-component histidine kinase encoded by the os-1/nik1 gene.
authors.affiliation: Faculty of Life Science, University of Toyo, Itakura, Oura-gun 374-0193, Japan. fujimura@itakura.toyo.ac.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Fujimura
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ochiai
authors.forename: Michiyo
authors.initials: M
authors.lastname: Oshima
authors.forename: Takayuki
authors.initials: T
authors.lastname: Motoyama
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ichiishi
authors.forename: Ron
authors.initials: R
authors.lastname: Usami
authors.forename: Koki
authors.initials: K
authors.lastname: Horikoshi
authors.forename: Isamu
authors.initials: I
authors.lastname: Yamaguchi
mesh_terms: D000595:Amino Acid Sequence; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000633:toxicity; D003001:Cloning, Molecular; D030541:Databases, Genetic; D004149:Dioxoles / Q000633:toxicity; D025141:Drug Resistance, Fungal; D005659:Fungicides, Industrial / Q000633:toxicity*; D005800:Genes, Fungal / Q000235:genetics*; D016681:Genome, Fungal; D006827:Hydantoins; D020930:MAP Kinase Kinase Kinases / Q000235:genetics*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics / Q000502:physiology; D009492:Neurospora crassa / Q000187:drug effects* / Q000201:enzymology*; D009996:Osmotic Fragility / Q000187:drug effects / Q000235:genetics*; D010641:Phenotype; D011758:Pyrroles / Q000633:toxicity; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D004149:Dioxoles; D005659:Fungicides, Industrial; D006827:Hydantoins; D011758:Pyrroles; D029701:Saccharomyces cerevisiae Proteins; D000620:Aminoimidazole Carboxamide; D020930:MAP Kinase Kinase Kinases; C476806:SSK22 protein, S cerevisiae; D020929:Mitogen-Activated Protein Kinase Kinases; C089356:PBS2 protein, S cerevisiae; C108339:fludioxonil; C033148:iprodione