Chromatin structure is important for controlling gene expression, but mechanisms underlying chromatin remodel- ing are not fully understood. Here we report that an FKBP （FK506 binding protein） type immunophilin, AtF...Chromatin structure is important for controlling gene expression, but mechanisms underlying chromatin remodel- ing are not fully understood. Here we report that an FKBP （FK506 binding protein） type immunophilin, AtFKBP53, possesses histone chaperone activity and is required for repressing ribosomal gene expression in Arabidopsis. The At- FKBP53 protein is a multidomain FKBP with a typical peptidylprolyl isomerase （PPIase） domain and several highly charged domains. Using nucleosome assembly assays, we showed that AtFKBP53 has histone chaperone activity and the charged acidic domains are sufficient for the activity. We show that AtFKBP53 interacts with histone H3 through the acidic domains, whereas the PPIase domain is dispensable for histone chaperone activity or histone binding. Ri- bosomal RNA gene （18S rDNA） is overexpressed when AtFKBP53 activity is reduced or eliminated in Arabidopsis plants. Chromatin immunoprecipitation assay showed that AtFKBP53 is associated with the 18S rDNA gene chro- matin, implicating that AtFKBP53 represses rRNA genes at the chromatin level. This study identifies a new histone chaperone in plants that functions in chromatin remodeling and regulation of transcription.展开更多
基金We thank Veder Garcia （University of California, Berkeley, USA） for critically reading the paper, Zengyong He for providing the AtFKBP53：：GUS transgenic line and Masami Horikoshi （The University of Tokyo, Japan） for the pET-6His-SpFkbp39P plasmid. This work was supported by grants from the National Science Foundation and US Department of Energy （toSL）.
文摘Chromatin structure is important for controlling gene expression, but mechanisms underlying chromatin remodel- ing are not fully understood. Here we report that an FKBP （FK506 binding protein） type immunophilin, AtFKBP53, possesses histone chaperone activity and is required for repressing ribosomal gene expression in Arabidopsis. The At- FKBP53 protein is a multidomain FKBP with a typical peptidylprolyl isomerase （PPIase） domain and several highly charged domains. Using nucleosome assembly assays, we showed that AtFKBP53 has histone chaperone activity and the charged acidic domains are sufficient for the activity. We show that AtFKBP53 interacts with histone H3 through the acidic domains, whereas the PPIase domain is dispensable for histone chaperone activity or histone binding. Ri- bosomal RNA gene （18S rDNA） is overexpressed when AtFKBP53 activity is reduced or eliminated in Arabidopsis plants. Chromatin immunoprecipitation assay showed that AtFKBP53 is associated with the 18S rDNA gene chro- matin, implicating that AtFKBP53 represses rRNA genes at the chromatin level. This study identifies a new histone chaperone in plants that functions in chromatin remodeling and regulation of transcription.
文摘目的探究长链非编码RNA核富集转录体1(long non-coding RNA paraspeckle assembly transcript 1,LncRNA-NEAT1)和微小RNA(micro RNA,miR)-93-5p在急性脑梗死(acute cerebral infarction,ACI)患者血清中的表达情况及临床意义。方法选取2020年1月~2022年2月河北北方学院附属第一医院收治的84例急性脑梗死患者作为脑梗死组,收集其临床资料,根据梗死病灶面积分为小面积梗死组、中面积梗死组和大面积梗死组;根据神经功能缺损程度分为轻度组、中度组和重度组;根据预后结局分为生存组和死亡组;同期健康体检者84例为对照组。采用实时荧光定量PCR法检测血清LncRNA-NEAT1和miR-93-5p表达水平;采用受试者工作特征(ROC)曲线分析血清LncRNANEAT1和miR-93-5p表达水平对急性脑梗死患者预后的预测效能。结果与对照组相比,脑梗死组血清LncRNANEAT1(2.46±0.38 vs 1.01±0.20)表达水平显著升高,miR-93-5p(0.42±0.16 vs 1.02±0.22)表达水平显著降低,差异具有统计学意义(t=30.948,33.796,均P<0.05)。血清LncRNA-NEAT1表达水平随梗死病灶面积(2.21±0.36,2.45±0.39,2.75±0.45)和神经功能缺损程度(2.24±0.34,2.46±0.40,2.70±0.45)增加而升高(F=11.434,8.674,均P<0.05),miR-93-5p表达水平(0.68±0.20,0.43±0.17,0.12±0.04)随梗死病灶面积和神经功能缺损程度(0.63±0.19,0.41±0.16,0.21±0.08)增加而降低,差异具有统计学意义(F=79.777,49.316,均P<0.05)。与生存组相比,死亡组血清LncRNA-NEAT1(2.78±0.43 vs 2.39±0.40)表达水平显著升高,miR-93-5p(0.28±0.09 vs 0.45±0.18)表达水平显著降低,差异具有统计学意义(t=3.378,3.550,均P<0.05)。血清LncRNA-NEAT1,miR-93-5p单独及联合预测急性脑梗死患者死亡的曲线下面积(AUC)分别为0.733(95%CI:0.591~0.876),0.784(95%CI:0.669~0.898)和0.849(95%CI:0.752~0.946),敏感度分别为53.3%,73.3%和86.7%,特异度分别为76.8%,75.4%和73.9%。结论LncRNANEAT1与miR-93-5p联合检测对急性脑梗死有一定预后预测价值。
