The CBP/p300 histone acetyltransferases function as plant-specific MEDIATOR subunits in Arabidopsis  

作　　者：Jing Guo Long Wei Shan-Shan Chen Xue-Wei Cai Yin-Na Su Lin Li She Chen Xin-Jian He 

机构地区：[1]National Institute of Biological Sciences,Beijing 102206,China [2]Graduate School of Peking Union Medical College,Beijing 100730,China [3]Tsinghua Institute of Multidisciplinary Biomedical Research,Tsinghua University,Beijing 100084,China

出　　处：《Journal of Integrative Plant Biology》2021年第4期755-771,共17页植物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(32025003);by the National Key Research and Development Program of China(2016YFA0500801)from the Chinese Ministry of Science and Technology。

摘　　要：In eukaryotes,MEDIATOR is a conserved multisubunit complex that links transcription factors and RNA polymerase II and that thereby facilitates transcriptional initiation.Although the composition of MEDIATOR has been well studied in yeast and mammals,relatively little is known about the composition of MEDIATOR in plants.By affinity purification followed by mass spectrometry,we identified 28 conserved MEDIATOR subunits in Arabidopsis thaliana,including putative MEDIATOR subunits that were not previously validated.Our results indicated that MED34,MED35,MED36,and MED37 are not Arabidopsis MEDIATOR subunits,as previously proposed.Our results also revealed that two homologous CBP/p300 histone acetyltransferases,HAC1 and HAC5(HAC1/5)are in fact plant-specific MEDIATOR subunits.The MEDIATOR subunits MED8 and MED25(MED8/25)are partially responsible for the association of MEDIATOR with HAC1/5,MED8/25 and HAC1/5 co-regulate gene expression and thereby affect flowering time and floral development.Our in vitro observations indicated that MED8 and HAC1 form liquid-like droplets by phase separation,and our in vivo observations indicated that these droplets co-localize in the nuclear bodies at a subset of nuclei.The formation of liquid-like droplets is required for MED8 to interact with RNA polymerase II.In summary,we have identified all of the components of Arabidopsis MEDIATOR and revealed the mechanism underlying the link of histone acetylation and transcriptional regulation.

关 键 词：COMPLEX development flowering time histone acetylation MEDIATOR phase separation TRANSCRIPTION 

分 类 号：Q943[生物学—植物学]