Histone acetylation is a major epigenetic control mechanism that is tightly linked to the promotion of gene expression. Histone acetylation levels are balanced through the opposing activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Arabidopsis HDAC genes (AtHDACs) compose a large gene family, and distinct phenotypes among AtHDAC mutants reflect the functional specificity of individual AtHDACs. However, the mechanisms underlying this functional diversity are largely unknown. Here, we show that POWERDRESS (PWR), a SANT (SWI3/DAD2/N-CoR/TFIII-B) domain protein, interacts with HDA9 and promotes histone H3 deacetylation, possibly by facilitating HDA9 function at target regions. The developmental phenotypes of pwr and hda9 mutants were highly similar. Three lysine residues (K9, K14, and K27) of H3 retained hyperacetylation status in both pwr and hda9 mutants. Genome-wide H3K9 and H3K14 acetylation profiling revealed elevated acetylation at largely overlapping sets of target genes in the two mutants. Highly similar gene-expression profiles in the two mutants correlated with the histone H3 acetylation status in the pwr and hda9 mutants. In addition, PWR and HDA9 modulated flowering time by repressing AGAMOUS-LIKE 19 expression through histone H3 deacetylation in the same genetic pathway. Finally, PWR was shown to physically interact with HDA9, and its SANT2 domain, which is homologous to that of subunits in animal HDAC complexes, showed specific binding affinity to acetylated histone H3. We therefore propose that PWR acts as a subunit in a complex with HDA9 to result in lysine deacetylation of histone H3 at specific genomic targets.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 2016 Dec 20|
Bibliographical noteFunding Information:
We thank Dr. Jeongsik Kim for the plasmid gCsVMV-3xHA-N-1300; Dr. Hui Kyung Cho for technical support; and Rae Eden Yumul for editing the manuscript. This work was supported by NIH Grant GM061146 (to Xuemei Chen); Gordon and Betty Moore Foundation Grant GBMF3046 (to Xuemei Chen); Guangdong Innovation Research Team Fund 2014ZT05S078 (to Xuemei Chen); IBS-R013-G2 (to J.M.K. and Y.-J.K.); and National Natural Science Foundation of China Grants 31570372 and 31671777 (to R.W. and L.X.). Work in X.Z.'s laboratory was supported by National Science Foundation CAREER Award MCB-1552455, the Alexander von Humboldt Foundation (Alfred Toepfer Faculty Fellow Award), and US Department of Agriculture and National Institute of Food and Agriculture Grant Hatch 1002874.
© 2016, National Academy of Sciences. All rights reserved.
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