title: The histone H3 lysine 9 methyltransferase DIM-5 modifies chromatin at frequency and represses light-activated gene expression.
abstract: The transcriptional program controlling the circadian rhythm requires coordinated regulation of chromatin. Characterization of the chromodomain helicase DNA-binding enzyme CHD1 revealed DNA methylation in the promoter of the central clock gene frequency (frq) in Neurospora crassa. In this report, we show that the DNA methylation at frq is not only dependent on the DNA methyltransferase DIM-2 but also on the H3K9 methyltransferase DIM-5 and HP1. Histone H3 lysine 9 trimethylation (H3K9me3) occurs at frq and is most prominent 30 min after light-activated expression. Strains lacking dim-5 have an increase in light-induced transcription, and more White Collar-2 is found associated with the frq promoter. Consistent with the notion that DNA methylation assists in establishing the proper circadian phase, loss of H3K9 methylation results in a phase advance suggesting it delays the onset of frq expression. The dim-5 deletion strain displays an increase in circadian-regulated conidia formation on race tubes and there is a synthetic genetic interaction between dim-5 and ras-1(bd). These results indicate DIM-5 has a regulatory role in muting circadian output. Overall, the data support a model where facultative heterochromatic at frq serves to establish the appropriate phase, mute the light response, and repress circadian output.
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Ruesch
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Mukund
authors.initials: M
authors.lastname: Ramakrishnan
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Hin S
authors.initials: HS
authors.lastname: Chong
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Riasat
authors.initials: R
authors.lastname: Zaman
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901.
authors.forename: Tammy M
authors.initials: TM
authors.lastname: Joska
authors.affiliation: Department of Animal Sciences, Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901 belden@aesop.rutgers.edu.
authors.forename: William J
authors.identifier: http://orcid.org/0000-0003-4765-9227
authors.initials: WJ
authors.lastname: Belden
mesh_terms: D002843:Chromatin; D047369:Chromatin Immunoprecipitation; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics*; D019175:DNA Methylation; D005656:Fungal Proteins / Q000235:genetics; D015870:Gene Expression / Q000528:radiation effects; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics*; D008027:Light; D009492:Neurospora crassa / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C087405:FRQ protein, Neurospora crassa; D005656:Fungal Proteins; D000090266:Chromobox Protein Homolog 5; D011495:Histone-Lysine N-Methyltransferase
keywords: DNA methylation; chromatin; circadian rhythm; heterochromatin