目的探究在紫外线暴露下环指蛋白20(ring finger protein 20,RNF20)低表达对胃癌细胞DNA损伤修复的影响及其相关作用机制。方法实验采用慢病毒载体构建稳定低表达胃癌细胞系,分为对照组和RNF20敲低组,用CCK-8法检测两组细胞的增殖情况,...目的探究在紫外线暴露下环指蛋白20(ring finger protein 20,RNF20)低表达对胃癌细胞DNA损伤修复的影响及其相关作用机制。方法实验采用慢病毒载体构建稳定低表达胃癌细胞系,分为对照组和RNF20敲低组,用CCK-8法检测两组细胞的增殖情况,用总共照射剂量为20 J/m^(2)紫外线照射胃癌MGC803细胞,采用Western blotting及免疫荧光技术检测两组细胞γ-H2AX、RAD51和p21的情况。结果荧光显微镜观察两组细胞均有绿色荧光蛋白表达;CCK-8显示RNF20表达降低会促进胃癌细胞增殖;敲低组细胞中RNF20蛋白较对照组表达降低。与对照组相比,经20 J/m^(2)紫外线照射细胞后,敲低组γ-H2AX消失更加迟缓,RAD51蛋白表达降低,p21蛋白表达下降趋势更慢。结论RNF20敲低会抑制紫外线诱导的胃癌细胞DNA损伤修复过程。展开更多
Autophagy is an evolutionarily conserved lysosome-mediated catabolic process（Klionsky,2007）.Autophagy is believed to be essential for cell survival,especially when cells were exposed to stresses,such as nutrient sta...Autophagy is an evolutionarily conserved lysosome-mediated catabolic process（Klionsky,2007）.Autophagy is believed to be essential for cell survival,especially when cells were exposed to stresses,such as nutrient starvation.展开更多
表观遗传修饰参与了药物成瘾的形成过程,而在药物成瘾过程中组蛋白泛素化水平的变化仍未可知。药物成瘾过程中常表现为多巴胺(dopamine, DA)表达量的升高,因此本研究欲探讨多巴胺升高对神经细胞组蛋白泛素化的影响及其机制。Western印...表观遗传修饰参与了药物成瘾的形成过程,而在药物成瘾过程中组蛋白泛素化水平的变化仍未可知。药物成瘾过程中常表现为多巴胺(dopamine, DA)表达量的升高,因此本研究欲探讨多巴胺升高对神经细胞组蛋白泛素化的影响及其机制。Western印迹结果显示,在终浓度0.8 mmol/L的多巴胺作用8 h后,人神经母细胞瘤细胞系SH-SY5Y细胞中环指蛋白20(ring finger protein 20, RNF20)表达量降低(0.29±0.032 vs. 1.0±0.025,P<0.0001),泛素化组蛋白H2B(H2Bub1)表达量下降(0.28±0.032 vs. 1.0±0.017,P<0.0001)。但是RT-PCR结果显示,多巴胺处理SH-SY5Y细胞后,RNF20在mRNA水平的表达无明显变化。在SH-SY5Y细胞中沉默RNF20的表达,H2Bub1在蛋白质水平的表达明显降低(0.20±0.069 vs. 1.0±0.060,P=0.001)。在加入多巴胺的基础上,分别加入蛋白酶体抑制剂MG132、自噬体形成抑制剂3-MA以及空泡型H^+-ATP酶特异性抑制剂Baf-A1等药物来检测RNF20的降解途径,结果发现,加入MG132、3-MA以及Baf-A1后,RNF20表达量均比DA处理组显著上升(1.51±0.095,P=0.0003; 0.89±0.075,P=0.0021; 2.74±0.099,P<0.0001;vs. 0.27±0.044)。上述结果表明,在SH-SY5Y细胞中,RNF20对H2Bub1具有调控作用,多巴胺可通过泛素化及自噬两种途径促进RNF20降解,从而抑制组蛋白H2B泛素化。展开更多
p53 is a key transcription factor to regulate gene transcription.However,the molecular mechanism of chromatin-associated p53 on gene transcription remains elusive.Here,using unbiased protein affinity purification,we f...p53 is a key transcription factor to regulate gene transcription.However,the molecular mechanism of chromatin-associated p53 on gene transcription remains elusive.Here,using unbiased protein affinity purification,we found that the RNF20/40 complex associated with p53 on the chromatin.Further analyses indicated that p53 mediated the recruitment of the RNF20/40 complex to p53 target gene loci including p21 and PUMA loci and regulated the transcription of p21 and PUMA via the RNF20/40 complex-dependent histone H2B ubiquitination(ubH2B).Lacking the RNF20/40 complex suppressed not only ubH2B but also the generation of the mature mRNA of p21 and PUMA.Moreover,ubH2B was recognized by the ubiquitin-binding motif of pre-mRNA processing splicing factor 8(PRPF8),a subunit in the spliceosome,and PRPF8 was required for the maturation of the mRNA of p21 and PUMA.Our study unveils a novel p53-dependent pathway that regulates mRNA splicing for tumor suppression.展开更多
RNF20,an E3 ligase critical for monoubiquitination of histone H2B at lysine 120(H2Bub),has been implicated in the regulation of various cellar processes;however,its physiological roles in adipocytes remain poorly char...RNF20,an E3 ligase critical for monoubiquitination of histone H2B at lysine 120(H2Bub),has been implicated in the regulation of various cellar processes;however,its physiological roles in adipocytes remain poorly characterized.Here,we report that the adipocyte-specific knockout of Rnf20(ASKO)in mice led to progressive fat toss,organomegaly and hyperinsulinemia.Despite signs of hyperinsulinemia,normal insulin sensitivity and improved glucose tolerance were observed in the young and aged CD-fed ASKO mice.In addition,high-fat diet-fed ASKO mice developed severe liver steatosis.Moreover,we observed that the ASKO mice were extremely sensitive to a cold environment due to decreased expression levels of brown adipose tissue(BAT)selective genes,including uncoupling protein 1(l/cpf),and impaired mitochondrial functions.Significantly decreased levels of peroxisome proliterator-activated receptor gamma(Ppary)were observed in the gonadal white adipose tissues(gWAT)from the ASKO mice,suggesting that Rnf20 regulates adipogenesis,at least in part,through Ppary.Rosiglitazone-treated ASKO mice exhibited increased fat mass compared to that of the non-treated ASKO mice.Collectively,our results illustrate the critical role of RNF20 in control of white and brown adipose tissue development and physiological function.展开更多
基金supported by the National Basic Research Program of China (973 Program)(No.2016YFA0100400)the National Natural Science Foundation of China(No.81773009)
文摘Autophagy is an evolutionarily conserved lysosome-mediated catabolic process（Klionsky,2007）.Autophagy is believed to be essential for cell survival,especially when cells were exposed to stresses,such as nutrient starvation.
文摘表观遗传修饰参与了药物成瘾的形成过程,而在药物成瘾过程中组蛋白泛素化水平的变化仍未可知。药物成瘾过程中常表现为多巴胺(dopamine, DA)表达量的升高,因此本研究欲探讨多巴胺升高对神经细胞组蛋白泛素化的影响及其机制。Western印迹结果显示,在终浓度0.8 mmol/L的多巴胺作用8 h后,人神经母细胞瘤细胞系SH-SY5Y细胞中环指蛋白20(ring finger protein 20, RNF20)表达量降低(0.29±0.032 vs. 1.0±0.025,P<0.0001),泛素化组蛋白H2B(H2Bub1)表达量下降(0.28±0.032 vs. 1.0±0.017,P<0.0001)。但是RT-PCR结果显示,多巴胺处理SH-SY5Y细胞后,RNF20在mRNA水平的表达无明显变化。在SH-SY5Y细胞中沉默RNF20的表达,H2Bub1在蛋白质水平的表达明显降低(0.20±0.069 vs. 1.0±0.060,P=0.001)。在加入多巴胺的基础上,分别加入蛋白酶体抑制剂MG132、自噬体形成抑制剂3-MA以及空泡型H^+-ATP酶特异性抑制剂Baf-A1等药物来检测RNF20的降解途径,结果发现,加入MG132、3-MA以及Baf-A1后,RNF20表达量均比DA处理组显著上升(1.51±0.095,P=0.0003; 0.89±0.075,P=0.0021; 2.74±0.099,P<0.0001;vs. 0.27±0.044)。上述结果表明,在SH-SY5Y细胞中,RNF20对H2Bub1具有调控作用,多巴胺可通过泛素化及自噬两种途径促进RNF20降解,从而抑制组蛋白H2B泛素化。
基金This work was supported by the National Natural Science Foundation of China(31670812 to C.W.)the grant for Returned Overseas Chinese Scholars of Hebei Province(CY201602 to C.W.)+1 种基金the Hundreds of Outstanding Talent Innovation Projects in Hebei Province(SLRC2017023 to C.W.)the Natural Science Foundation of Hebei Province(C2018201171 to C.W.).
文摘p53 is a key transcription factor to regulate gene transcription.However,the molecular mechanism of chromatin-associated p53 on gene transcription remains elusive.Here,using unbiased protein affinity purification,we found that the RNF20/40 complex associated with p53 on the chromatin.Further analyses indicated that p53 mediated the recruitment of the RNF20/40 complex to p53 target gene loci including p21 and PUMA loci and regulated the transcription of p21 and PUMA via the RNF20/40 complex-dependent histone H2B ubiquitination(ubH2B).Lacking the RNF20/40 complex suppressed not only ubH2B but also the generation of the mature mRNA of p21 and PUMA.Moreover,ubH2B was recognized by the ubiquitin-binding motif of pre-mRNA processing splicing factor 8(PRPF8),a subunit in the spliceosome,and PRPF8 was required for the maturation of the mRNA of p21 and PUMA.Our study unveils a novel p53-dependent pathway that regulates mRNA splicing for tumor suppression.
基金This research was funded by the National Natural Science Foundation of China(31672387)National Science Foundation for Distinguished Young Scholars(31925036)+2 种基金National Key Research and Development Program of China(2020YFC1316602)Sichuan Province&Chinese Academy of Science of Science&Technology Cooperation Project(2017JZ0025)the Agricultural Science and Technology Innovation program(ASTIP-IAS05).
文摘RNF20,an E3 ligase critical for monoubiquitination of histone H2B at lysine 120(H2Bub),has been implicated in the regulation of various cellar processes;however,its physiological roles in adipocytes remain poorly characterized.Here,we report that the adipocyte-specific knockout of Rnf20(ASKO)in mice led to progressive fat toss,organomegaly and hyperinsulinemia.Despite signs of hyperinsulinemia,normal insulin sensitivity and improved glucose tolerance were observed in the young and aged CD-fed ASKO mice.In addition,high-fat diet-fed ASKO mice developed severe liver steatosis.Moreover,we observed that the ASKO mice were extremely sensitive to a cold environment due to decreased expression levels of brown adipose tissue(BAT)selective genes,including uncoupling protein 1(l/cpf),and impaired mitochondrial functions.Significantly decreased levels of peroxisome proliterator-activated receptor gamma(Ppary)were observed in the gonadal white adipose tissues(gWAT)from the ASKO mice,suggesting that Rnf20 regulates adipogenesis,at least in part,through Ppary.Rosiglitazone-treated ASKO mice exhibited increased fat mass compared to that of the non-treated ASKO mice.Collectively,our results illustrate the critical role of RNF20 in control of white and brown adipose tissue development and physiological function.
