目的本研究旨在探讨转录共激活因子(transcriptional coactivator with PDZ-binding motif,TAZ)与组蛋白H2A(histone H2A,H2A)的一种组蛋白变体H2A.Z,在缺氧诱导的肺损伤后修复中的作用及其潜在机制。方法利用缺氧模拟仓(5800 m)处理4 d后,构建小鼠缺氧肺损伤模型,肺组织切片HE染色评估肺损伤程度。利用缺氧工作站(1%O_2浓度)处理小鼠肺泡上皮细胞系(murine lung epithelial-12,MLE12)24 h,构建MLE12缺氧细胞模型,Western blot分析检测TAZ表达。CCK-8实验评价肺泡上皮细胞(alveolar epithelial cells,AECs)增殖。免疫共沉淀(co-immunoprecipitation,Co-IP)实验验证TAZ与H2A.Z二者之间的相互作用。靶向剪切及转座酶标记技术(cleavage under targets and tagmentation,CUT&Tag)测序分析TAZ影响H2A.Z在染色质沉积情况。结果缺氧显著诱导小鼠肺组织肺泡萎缩及炎症浸润(P<0.01)。缺氧培养显著上调MLE12细胞中TAZ蛋白表达(P<0.05)。CCK-8实验发现,敲低TAZ后AECs增殖能力显著下降(P<0.01)。Co-IP证实TAZ与H2A.Z存在物理相互作用。靶向剪切及转座酶标记技术(cleavage under targets and tagmentation,CUT&Tag)测序显示缺氧促进H2A.Z在染色质上的沉积(常氧结合位点31817,缺氧结合位点44078),而TAZ敲低部分逆转此现象(结合位点37840)。结论缺氧显著上调TAZ表达,后者与H2A.Z的结合并促进H2A.Z在染色质上的沉积,增强AECs增殖以应对缺氧损伤。
Trimethylation of histone {2}3K4({2}3K4me3)is widely distributed at numerous actively transcribed protein-coding genes throughout the genome.{2}owever,the interplay between {2}3K4me3 and other chromatin modifications in plants remains poorly understood.In this study,we show that the Arabidopsis thaliana ALFIN-LIKE(AL)proteins contain a C-terminal P{2}D finger capable of binding to {2}3K4me3 and a P{2}D-associated AL(PAL)domain that interacts with components of the Polycomb repressive complex 1,thereby facilitating {2}2A ubiquitination({2}2Aub)at {2}3K4me3-enriched genes throughout the genome.Furthermore,we demonstrate that loss of function of SDG2,encoding a key histone {2}3K4 methyltransferase,leads to a reduction in {2}3K4me3 level,which subsequently causes a genome-wide decrease in {2}2Aub,revealing a strong association between {2}3K4me3 and {2}2Aub.Finally,we discover that the PAL domain of AL proteins interacts with various other chromatin-related proteins or complexes,including those involved in regulating {2}2A.Z deposition,{2}3K27me3 demethylation,histone deacetylation,and chromatin accessibility.Our genome-wide analysis suggests that the AL proteins play a crucial role in coordinating {2}3K4me3 with multiple other chromatin modifications across the genome.
Xiao-Min SuDan-Yang YuanNa LiuZhao-Chen ZhangMinqi YangLin LiShe ChenYue ZhouXin-Jian He
