[符宏勇/施臥虎] 阿拉伯芥去泛素化酵素OTU5藉修飾組蛋白促進主要開花抑制因子FLC、MAF4、MAF5之表現調控開花

Arabidopsis OTU5 is a novel flowering suppressor. OTU5 acts, in an associated protein complex (OTU5c), in parallel with SWR1c- and HUB1/2-mediated pathways to epigenetically activate FLC clade repressors and suppress flowering. OTU5 primarily activates FLC and, to a lesser extent, MAF5, MAF4, and MAF1, which in turn suppress major flowering initiators FT and SOC1 to repress flowering. OTU5 is involved in increasing the deposition of the activating histone mark H3K36me3 and in the downregulation of the suppressive histone marks H3K27me3 and H3K9me2 as well as ubH2B on specific loci, such as FLC, MAF4, and MAF5. OTU5-mediated flowering suppression is distinct from the SWR1c-mediated pathway, which activates FLC-related repressors through H2A.Z deposition. OTU5 also acts independently of the HUB1/2-mediated pathway, which modulates genome-wide ubH2B levels and activates a distinct set of FLC-related repressors through distinct activating/repressive histone marks. OTU5 is, however, partially required for FLC-mediated flowering suppression in autonomous pathway mutants and FRIGIDA-Col.