Abstract:
Chromatin dynamics play essential roles in transcriptional regulation. The chromodomain helicase DNA-binding domain 3 (CHD3) chromatin remodeler PICKLE (PKL) and HISTONE DEACETYLASE6 (HDA6) are required for transcriptional gene silencing, but their coordinated function in gene repression requires further study. Through a genetic suppressor screen, we found that a point mutation at PKL could partially restore the developmental defects of a weak Polycomb repressive complex 1 (PRC1) mutant (ring1a-2 ring1b-3), in which RING1A expression is suppressed by a T-DNA insertion at the promoter. Compared to ring1a-2 ring1b-3, the expression of RING1A is increased, nucleosome occupancy is reduced, and the histone 3 lysine 9 acetylation (H3K9ac) level is increased at the RING1A locus in the pkl ring1a-2 ring1b-3 triple mutant. HDA6 interacts with PKL and represses RING1A expression similarly to PKL genetically and molecularly in the ring1a-2 ring1b-3 background. Furthermore, we show that PKL and HDA6 suppress the expression of a set of genes and transposable elements (TEs) by increasing nucleosome density and reducing H3K9ac. Genome-wide analysis indicated they possibly coordinately maintain DNA methylation as well. Our findings suggest that PKL and HDA6 function together to reduce H3K9ac and increase nucleosome occupancy, thereby facilitating gene/TE regulation in Arabidopsis (Arabidopsis thaliana).
摘要:
染色质动力学在转录调控中起重要作用。色域解旋酶DNA结合域3(CHD3)染色质重塑因子PICKLE(PKL)和HISTONEDEACETYLASE6(HDA6)是转录基因沉默所必需的,但是它们在基因抑制中的协调功能需要进一步研究。通过基因抑制筛选,我们发现,PKL的点突变可以部分恢复弱Polycomb抑制复合物1(PRC1)突变体(ring1a-2ring1b-3)的发育缺陷,其中RING1A表达被启动子处的T-DNA插入抑制。与ring1a-2ring1b-3相比,RING1A的表达增加,核小体占用减少,在pklring1a-2ring1b-3三重突变体中,RING1A基因座的组蛋白3赖氨酸9乙酰化(H3K9ac)水平增加。HDA6与PKL相互作用,并在环1a-2环1b-3背景中与PKL在遗传和分子上相似地抑制RING1A表达。此外,我们显示PKL和HDA6通过增加核小体密度和减少H3K9ac来抑制一组基因和转座因子(TE)的表达。全基因组分析表明,它们也可能协调维持DNA甲基化。我们的研究结果表明,PKL和HDA6共同发挥作用,以减少H3K9ac和增加核小体占有率,从而促进拟南芥(拟南芥)中的基因/TE调控。