title: Rhythmic oscillation of histone acetylation and methylation at the Arabidopsis central clock loci.
abstract: Circadian clock genes are regulated by a transcriptional-translational feedback loop. In Arabidopsis, LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) transcripts are highly expressed in the morning. Translated LHY and CCA1 proteins repress the expression of TIMING OF CAB EXPRESSION 1 (TOC1), which peaks in the evening. TOC1 protein induces expression of LHY and CCA1, forming a negative feedback loop which is believed to constitute the oscillatory mechanism of the clock. The rhythmic oscillation of mouse clock genes mPERIOD 1 (mPER1) and mPER2 has been correlated with regular alteration of chromatin structure through histone acetylation/deacetylation. However, little is known about the relationship between the transcriptional activity of Arabidopsis clock genes and their chromatin status. Here, we report that histone H3 acetylation (H3Ac) and H3 lysine 4 tri-methylation (H3K4me3) levels at LHY, CCA1, and TOC1 are positively correlated with the rhythmic transcript levels of these genes, whereas H3K36me2 level shows a negative correlation. Thus, our study suggests rhythmic transcription of Arabidopsis clock genes might be regulated by rhythmic histone modification, and it provides a platform for future identification of clock-controlling histone modifiers.
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul, 151-747, Korea.
authors.forename: Hae-Ryong
authors.initials: HR
authors.lastname: Song
authors.forename: Yoo-Sun
authors.initials: YS
authors.lastname: Noh
mesh_terms: D000107:Acetylation; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D057906:Circadian Clocks / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D008745:Methylation; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D004268:DNA-Binding Proteins; D006657:Histones; C113192:LHY protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D008239:Lysine