To improve catalytic activity of ribozyme on its substrate, the multi-ribozyme expression system was designed and constructed from 20 cis-acting hammerhead ribozymes undergoing self-cleavage with 10 trans-acting hamme...To improve catalytic activity of ribozyme on its substrate, the multi-ribozyme expression system was designed and constructed from 20 cis-acting hammerhead ribozymes undergoing self-cleavage with 10 trans-acting hammerhead ribozymes inserted alternatively regularly and the plasmid of pGEM-MDR1/MRP1 used to transcribe the MDR1/MRPl（196/210） substrate containing double target sites was also constructed by DNA recombination. Endonuclease digestion analysis and DNA sequencing indicate all the recombinant plasmids were correct. The clea- vage activities were evaluated for the multi-ribozyme expression system on the MDR1/MRP1 substrate in the cell free system. The results demonstrate that the cis-acting hammerhead ribozymes in the multi-ribozyme expression system were able to cleave themselves and the 72 nt of 196Rz and the 71 nt of 210Rz trans-acting hammerhead ribozymes were liberated effectively, and the trans-acting hammerhead ribozymes released were able to act on the MDR1/MRP1 double target RNA substrate and cleave the target RNA at specific sites effectively. The multi- ribozyme expression system of the [Coat＇A196Rz/Coat＇B210Rz]5 is more significantly superior to that of the [Coat＇A 196Rz/Coat＇B210Rz] 1 in cleavage of RNA substrate. The fractions cleaved by [Coat＇A 196Rz/Coat＇B210Rz]5 on the MDR1/MRP1 substrate for 8 h at observed temperatures showed no marked difference. The studies of Mg^2＋ on cleavage efficiency indicate that cleavage reaction is dependent on Mg^2＋ ions concentration. The plot of lg（kobs） vs. lgc（Mg^2＋） displays a linear relationship between 2.5 mmol/L and 20 mmol/L Mg^2＋. It suggests that Mg^2＋ ions play a crucial role in multi-ribozyme cleavage on the substrate.展开更多
目的探讨胆盐载体MRP1、MRP2在妊娠期肝内胆汁淤积症(ICP)胎盘的表达,分析胎盘胆盐载体与ICP发病的关系。方法收集8例正常早孕妇女绒毛组织、7例正常中孕妇女胎盘组织、20例正常晚孕妇女(对照组)胎盘组织,以及20例ICP患者胎盘组织,检测...目的探讨胆盐载体MRP1、MRP2在妊娠期肝内胆汁淤积症(ICP)胎盘的表达,分析胎盘胆盐载体与ICP发病的关系。方法收集8例正常早孕妇女绒毛组织、7例正常中孕妇女胎盘组织、20例正常晚孕妇女(对照组)胎盘组织,以及20例ICP患者胎盘组织,检测收集组织中胆盐载体MRP1和MRP2 mRNA的表达。结果ICP和正常妊娠各期胎盘组织中均有MRP2 mRNA的表达,而MRP1 mRNA在大部分标本上有表达;ICP组MRP1 mRNA和MRP2 mRNA表达量与对照组相比(99.94±73.17 vs 99.20±68.65;95.78±56.50 vs 142.20±91.27)差异无统计学意义(P>0.05);ICP组未用地塞米松治疗胎盘MRP2 mRNA表达量低于对照组(91.82±48.08 vs 142.20±91.27,P<0.05)。结论在未用地塞米松治疗的ICP患者胎盘组织中,MRP2 mRNA的表达量降低,这可能是引起ICP患者胎盘胆汁酸转运障碍,从而引起胎儿体内胆汁淤积的机制之一。展开更多
目的体外HepG2细胞培养观察芒果苷(mangiferin)对多耐药相关蛋白3(multidrug resistance-associate protein 3,MRP3)和核受体孕烷X受体(pregnane X receptor,PXR)、CYP7A启动子结合因子(CYP7A promoter-binding factor,CPF)表达的影响...目的体外HepG2细胞培养观察芒果苷(mangiferin)对多耐药相关蛋白3(multidrug resistance-associate protein 3,MRP3)和核受体孕烷X受体(pregnane X receptor,PXR)、CYP7A启动子结合因子(CYP7A promoter-binding factor,CPF)表达的影响。方法用芒果苷刺激HepG2细胞72 h后,分别抽提细胞RNA、膜蛋白及核蛋白,采用半定量RT-PCR和蛋白免疫印迹检测膜转运蛋白MRP3和核受体PXR、CPF在转录与蛋白水平的表达变化。熊脱氧胆酸(ursode-oxycholic acid,UDCA)处理的HepG2细胞作为阳性对照、DMSO处理细胞为阴性对照。结果芒果苷可显著刺激HepG2细胞膜转运蛋白MRP3的mRNA(比阴性对照组高3.0倍,P<0.05)和蛋白(比阴性对照组高3.3倍,P<0.05)表达,其作用强于UDCA。芒果苷也可明显上调核受体PXR[mRNA水平增高1.7倍(P<0.05),蛋白水平增高3.7倍(P<0.01)]、CPF[mRNA水平增高2.1倍(P<0.05),蛋白水平增高4.9倍(P<0.05)]的表达。结论芒果苷刺激肝癌细胞HepG2细胞膜转运蛋白MRP3的表达上调可能与核受体PXR、CPF途径相关。展开更多
目的通过体外细胞培养和建立大鼠胆管结扎(b ile duct ligation,BDL)所致阻塞性胆汁淤积动物模型,在蛋白水平观察多耐药相关蛋白MRP3(mu ltidrug resistance-assoc iated prote in 3,MRP3)和核受体RXRα(retinoid-X receptor al-pha,RXR...目的通过体外细胞培养和建立大鼠胆管结扎(b ile duct ligation,BDL)所致阻塞性胆汁淤积动物模型,在蛋白水平观察多耐药相关蛋白MRP3(mu ltidrug resistance-assoc iated prote in 3,MRP3)和核受体RXRα(retinoid-X receptor al-pha,RXRα)表达的关系。方法用鹅去氧胆酸(chenodeoxycholic ac id,CDCA)或苯巴比妥(phenobarb ital,PB)分别刺激培养的肝癌细胞HepG2并建立DBL阻塞性胆汁淤积大鼠模型后,分别抽提HepG2细胞总蛋白、核蛋白和大鼠肝脏细胞膜蛋白和核蛋白,W estern b lot方法检测MRP3和RXRα蛋白表达水平的变化。结果在细胞水平,CDCA和PB可诱导HepG2细胞膜MRP3蛋白表达增高,并抑制细胞核RXRα蛋白表达;在动物体内,BDL大鼠肝脏MRP3明显增加,同时RXRα表达明显下降。结论肝细胞膜蛋白MRP3表达的上调可能与核受体RXRα表达抑制有关。展开更多
基金Supported by Fund of Shenzhen Bureau of Science and Technology, China(No.20008).
文摘To improve catalytic activity of ribozyme on its substrate, the multi-ribozyme expression system was designed and constructed from 20 cis-acting hammerhead ribozymes undergoing self-cleavage with 10 trans-acting hammerhead ribozymes inserted alternatively regularly and the plasmid of pGEM-MDR1/MRP1 used to transcribe the MDR1/MRPl（196/210） substrate containing double target sites was also constructed by DNA recombination. Endonuclease digestion analysis and DNA sequencing indicate all the recombinant plasmids were correct. The clea- vage activities were evaluated for the multi-ribozyme expression system on the MDR1/MRP1 substrate in the cell free system. The results demonstrate that the cis-acting hammerhead ribozymes in the multi-ribozyme expression system were able to cleave themselves and the 72 nt of 196Rz and the 71 nt of 210Rz trans-acting hammerhead ribozymes were liberated effectively, and the trans-acting hammerhead ribozymes released were able to act on the MDR1/MRP1 double target RNA substrate and cleave the target RNA at specific sites effectively. The multi- ribozyme expression system of the [Coat＇A196Rz/Coat＇B210Rz]5 is more significantly superior to that of the [Coat＇A 196Rz/Coat＇B210Rz] 1 in cleavage of RNA substrate. The fractions cleaved by [Coat＇A 196Rz/Coat＇B210Rz]5 on the MDR1/MRP1 substrate for 8 h at observed temperatures showed no marked difference. The studies of Mg^2＋ on cleavage efficiency indicate that cleavage reaction is dependent on Mg^2＋ ions concentration. The plot of lg（kobs） vs. lgc（Mg^2＋） displays a linear relationship between 2.5 mmol/L and 20 mmol/L Mg^2＋. It suggests that Mg^2＋ ions play a crucial role in multi-ribozyme cleavage on the substrate.
文摘目的探讨胆盐载体MRP1、MRP2在妊娠期肝内胆汁淤积症(ICP)胎盘的表达,分析胎盘胆盐载体与ICP发病的关系。方法收集8例正常早孕妇女绒毛组织、7例正常中孕妇女胎盘组织、20例正常晚孕妇女(对照组)胎盘组织,以及20例ICP患者胎盘组织,检测收集组织中胆盐载体MRP1和MRP2 mRNA的表达。结果ICP和正常妊娠各期胎盘组织中均有MRP2 mRNA的表达,而MRP1 mRNA在大部分标本上有表达;ICP组MRP1 mRNA和MRP2 mRNA表达量与对照组相比(99.94±73.17 vs 99.20±68.65;95.78±56.50 vs 142.20±91.27)差异无统计学意义(P>0.05);ICP组未用地塞米松治疗胎盘MRP2 mRNA表达量低于对照组(91.82±48.08 vs 142.20±91.27,P<0.05)。结论在未用地塞米松治疗的ICP患者胎盘组织中,MRP2 mRNA的表达量降低,这可能是引起ICP患者胎盘胆汁酸转运障碍,从而引起胎儿体内胆汁淤积的机制之一。
文摘目的体外HepG2细胞培养观察芒果苷(mangiferin)对多耐药相关蛋白3(multidrug resistance-associate protein 3,MRP3)和核受体孕烷X受体(pregnane X receptor,PXR)、CYP7A启动子结合因子(CYP7A promoter-binding factor,CPF)表达的影响。方法用芒果苷刺激HepG2细胞72 h后,分别抽提细胞RNA、膜蛋白及核蛋白,采用半定量RT-PCR和蛋白免疫印迹检测膜转运蛋白MRP3和核受体PXR、CPF在转录与蛋白水平的表达变化。熊脱氧胆酸(ursode-oxycholic acid,UDCA)处理的HepG2细胞作为阳性对照、DMSO处理细胞为阴性对照。结果芒果苷可显著刺激HepG2细胞膜转运蛋白MRP3的mRNA(比阴性对照组高3.0倍,P<0.05)和蛋白(比阴性对照组高3.3倍,P<0.05)表达,其作用强于UDCA。芒果苷也可明显上调核受体PXR[mRNA水平增高1.7倍(P<0.05),蛋白水平增高3.7倍(P<0.01)]、CPF[mRNA水平增高2.1倍(P<0.05),蛋白水平增高4.9倍(P<0.05)]的表达。结论芒果苷刺激肝癌细胞HepG2细胞膜转运蛋白MRP3的表达上调可能与核受体PXR、CPF途径相关。
文摘目的通过体外细胞培养和建立大鼠胆管结扎(b ile duct ligation,BDL)所致阻塞性胆汁淤积动物模型,在蛋白水平观察多耐药相关蛋白MRP3(mu ltidrug resistance-assoc iated prote in 3,MRP3)和核受体RXRα(retinoid-X receptor al-pha,RXRα)表达的关系。方法用鹅去氧胆酸(chenodeoxycholic ac id,CDCA)或苯巴比妥(phenobarb ital,PB)分别刺激培养的肝癌细胞HepG2并建立DBL阻塞性胆汁淤积大鼠模型后,分别抽提HepG2细胞总蛋白、核蛋白和大鼠肝脏细胞膜蛋白和核蛋白,W estern b lot方法检测MRP3和RXRα蛋白表达水平的变化。结果在细胞水平,CDCA和PB可诱导HepG2细胞膜MRP3蛋白表达增高,并抑制细胞核RXRα蛋白表达;在动物体内,BDL大鼠肝脏MRP3明显增加,同时RXRα表达明显下降。结论肝细胞膜蛋白MRP3表达的上调可能与核受体RXRα表达抑制有关。
