title: A novel cryptochrome-dependent oscillator in Neurospora crassa.
abstract: Several lines of evidence suggest that the circadian clock is constructed of multiple molecular feedback oscillators that function to generate robust rhythms in organisms. However, while core oscillator mechanisms driving specific behaviors are well described in several model systems, the nature of other potential circadian oscillators is not understood. Using genetic approaches in the fungus Neurospora crassa, we uncovered an oscillator mechanism that drives rhythmic spore development in the absence of the well-characterized FRQ/WCC oscillator (FWO) and in constant light, conditions under which the FWO is not functional. While this novel oscillator does not require the FWO for activity, it does require the blue-light photoreceptor CRYPTOCHROME (CRY); thus, we call it the CRY-dependent oscillator (CDO). The CDO was uncovered in a strain carrying a mutation in cog-1 (cry-dependent oscillator gate-1), has a period of ∼1 day in constant light, and is temperature-compensated. In addition, cog-1 cells lacking the circadian blue-light photoreceptor WC-1 respond to blue light, suggesting that alternate light inputs function in cog-1 mutant cells. We show that the blue-light photoreceptors VIVID and CRY compensate for each other and for WC-1 in CRY-dependent oscillator light responses, but that WC-1 is necessary for circadian light entrainment.
authors.affiliation: Center for Biological Clocks Research, Program for the Biology of Filamentous Fungi, and Department of Biology, Texas A&M University, College Station, Texas 77843.
authors.forename: Imade Y
authors.initials: IY
authors.lastname: Nsa
authors.affiliation: Center for Biological Clocks Research, Program for the Biology of Filamentous Fungi, and Department of Biology, Texas A&M University, College Station, Texas 77843.
authors.forename: Nirmala
authors.initials: N
authors.lastname: Karunarathna
authors.affiliation: Center for Biological Clocks Research, Program for the Biology of Filamentous Fungi, and Department of Biology, Texas A&M University, College Station, Texas 77843.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Center for Biological Clocks Research, Program for the Biology of Filamentous Fungi, and Department of Biology, Texas A&M University, College Station, Texas 77843.
authors.forename: Howard
authors.initials: H
authors.lastname: Huang
authors.affiliation: Center for Biological Clocks Research, Program for the Biology of Filamentous Fungi, and Department of Biology, Texas A&M University, College Station, Texas 77843.
authors.forename: Brittni
authors.initials: B
authors.lastname: Boetteger
authors.affiliation: Center for Biological Clocks Research, Program for the Biology of Filamentous Fungi, and Department of Biology, Texas A&M University, College Station, Texas 77843 dpedersen@bio.tamu.edu.
authors.forename: Deborah
authors.initials: D
authors.lastname: Bell-Pedersen
mesh_terms: D002940:Circadian Rhythm; D056931:Cryptochromes / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D009492:Neurospora crassa / Q000235:genetics* / Q000502:physiology; D013172:Spores, Fungal / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D056931:Cryptochromes; D004268:DNA-Binding Proteins; C087405:FRQ protein, Neurospora crassa; D005656:Fungal Proteins; D014157:Transcription Factors; C423283:VVD protein, Neurospora crassa; C105589:wc-1 protein, Neurospora crassa
keywords: FRQ-WCC oscillator; FRQ-less oscillator; circadian clock; cryptochrome; oscillator