title: Transcriptional repression of frequency by the IEC-1-INO80 complex is required for normal Neurospora circadian clock function.
abstract: Rhythmic activation and repression of the frequency (frq) gene are essential for normal function of the Neurospora circadian clock. WHITE COLLAR (WC) complex, the positive element of the Neurospora circadian system, is responsible for stimulation of frq transcription. We report that a C2H2 finger domain-containing protein IEC-1 and its associated chromatin remodeling complex INO80 play important roles in normal Neurospora circadian clock function. In iec-1KO strains, circadian rhythms are abolished, and the frq transcript levels are increased compared to that of the wild-type strain. Similar results are observed in mutant strains of the INO80 subunits. Furthermore, ChIP data show that recruitment of the INO80 complex to the frq promoter is IEC-1-dependent. WC-mediated transcription of frq contributes to the rhythmic binding of the INO80 complex at the frq promoter. As demonstrated by ChIP analysis, the INO80 complex is required for the re-establishment of the dense chromatin environment at the frq promoter. In addition, WC-independent frq transcription is present in ino80 mutants. Altogether, our data indicate that the INO80 complex suppresses frq transcription by re-assembling the suppressive mechanisms at the frq promoter after transcription of frq.
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Kexin
authors.initials: K
authors.lastname: Gai
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Zhaolan
authors.initials: Z
authors.lastname: Ding
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Yashang
authors.initials: Y
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America.
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Qun
authors.initials: Q
authors.lastname: He
mesh_terms: D002843:Chromatin / Q000235:genetics; D057906:Circadian Clocks / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D046912:Multiprotein Complexes / Q000235:genetics; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; C087405:FRQ protein, Neurospora crassa; D005656:Fungal Proteins; D046912:Multiprotein Complexes; D014157:Transcription Factors; C103772:white collar 2 protein, Neurospora