AUTHOR=Hung Fu-Yu , Chen Fang-Fang , Li Chenlong , Chen Chen , Chen Jian-Hao , Cui Yuhai , Wu Keqiang 

TITLE=The LDL1/2-HDA6 Histone Modification Complex Interacts With TOC1 and Regulates the Core Circadian Clock Components in Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00233

DOI=10.3389/fpls.2019.00233

ISSN=1664-462X

ABSTRACT=<p>In <italic>Arabidopsis</italic>, the circadian rhythm is associated with multiple important biological processes and maintained by multiple interconnected loops that generate robust rhythms. The circadian clock central loop is a negative feedback loop composed of the core circadian clock components. <italic>TOC1</italic> (<italic>TIMING OF CAB EXPRESSION 1</italic>) is highly expressed in the evening and negatively regulates the expression of <italic>CCA1</italic> (<italic>CIRCADIAN CLOCK ASSOCIATED 1</italic>)/<italic>LHY</italic> (<italic>LATE ELONGATED HYPOCOTYL</italic>). CCA1/LHY also binds to the promoter of <italic>TOC1</italic> and represses the <italic>TOC1</italic> expression. Our recent research revealed that the histone modification complex comprising of LYSINE-SPECIFIC DEMETHYLASE 1 (LSD1)-LIKE 1/2 (LDL1/2) and HISTONE DEACETYLASE 6 (HDA6) can be recruited by CCA1/LHY to repress <italic>TOC1</italic> expression. In this study, we found that HDA6, LDL1, and LDL2 can interact with TOC1, and the LDL1/2-HDA6 complex is associate with TOC1 to repress the <italic>CCA1/LHY</italic> expression. Furthermore, LDL1/2-HDA6 and TOC1 co-target a subset of genes involved in the circadian rhythm. Collectively, our results indicate that the LDL1/2-HDA6 histone modification complex is important for the regulation of the core circadian clock components.</p>