title: Spermidine determines the sensitivity to the calmodulin antagonist, chlorpromazine, for the circadian conidiation rhythm but not for the mycelial growth in Neurospora crassa.
abstract: The gene that suppresses the phenotype of the cpz-2 mutation, which results in changing the sensitivity to chlorpromazine in relation to mycelial growth and circadian rhythms, was cloned in Neurospora crassa. This gene is not the cpz-2 gene itself but rather is identical to the spe-3 gene that encodes spermidine synthase in Neurospora. The intracellular content of spermidine was lowered in the cpz-2 strain compared to that of the wild-type strain. By integration of the spe-3 gene or by the addition of spermidine into culture medium, the temperature sensitivity of mycelial growth was lost and the conidiation rhythm became sensitive to chlorpromazine in the cpz-2 strain, as was observed in the wild-type strain, but the hypersensitivity of mycelial growth on chlorpromazine in the cpz-2 strain was not affected. Therefore, it appears that spermidine determines only the sensitivity of the conidiation rhythm to chlorpromazine.
authors.affiliation: Department of Biology, Faculty of Science, Okayama University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Katagiri
authors.forename: K
authors.initials: K
authors.lastname: Onai
authors.forename: H
authors.initials: H
authors.lastname: Nakashima
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002746:Chlorpromazine / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects*; D004271:DNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D018492:Dopamine Antagonists / Q000494:pharmacology*; D015723:Gene Library; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000187:drug effects* / Q000254:growth & development*; D010641:Phenotype; D013095:Spermidine / Q000494:pharmacology*
chemical_list: D002147:Calmodulin; D004271:DNA, Fungal; D018492:Dopamine Antagonists; D002746:Chlorpromazine; D013095:Spermidine