摘要
目的 观察丙型肝炎病毒(HCV)RNA特异性脱氧核酶的体外剪切活性,探讨其用于抗病毒基因调控的可能性。 方法 以HCV 5’-非编码区及部分C区(5’-NCR-C)中两个具有5’…A ↓ U…3’特征的序列为靶位,以5’GGCTAGCTACAACGA3‘为活性中心,设计并合成两端经硫代修饰的脱氧核酶(TDRz),即TDRz-127和TDRz1。用Nar 1将质粒pHCV-neo完全线性化后,以之为模板体外转录获取HCV 5’-NCR-C;用碱性磷酸酶去除其5’端磷酸,再用T4聚核苷酸激酶和γ-32P-ATP进行5’端放射陛标记。在pH7.5、Mg2+10 mmol/L等条件下,将两种TDRz分别(5μmol/L)或共同(各2.5μmol/L)与底物RNA(200 nmol/L)混合,经变性、复性后于37℃孵育,分别于不同的时间点取出等份终止反应。以8％变性聚丙烯酰胺凝胶电泳和放射自显影分离、显示剪切产物,在凝胶成像分析仪上分析各条带光密度值并计算剪切百分率。 结果 在所设常用反应条件下于37℃孵育15、30、45、60、75、90min后,TDRz-127的剪切百分率分别达8.3％、16.1％、24.3％、26.2％、29.4％和31.1％,TDRzl的剪切百分率分别达7.4％,13.0％、15.6％、18.7％、19.4％和20.3％,两者同时剪切时的百分率约15.1％、29.6％、37.8％、39.1％、41.5％、42.6％。结论 TDRz-127和TDRzl对HCV
Objectives To analyze the cleavage activity of two deoxyribozymes targeting at hepatitis C virus (HCV) RNA in vitro and evaluate their prospects of antiviral therapy. Methods Two specific sequences containing 5'…A ↓U…3' inHCV 5' -noncoding region and 5' -fragment of C region (5' -NCR-C) were selected as the target sites, and with the active region of 5'GGCTAGCTACAACGA3', two phosphorothioate deoxyribozymes (TDRz) named as TDRz-127 and TDRzl were synthesized. HCV RNA 5'-NCR-C was transcribed in vitro from plasmid pHCV-neo which was completely linearized with restriction endonuclease Nar I, and its 5' -end phosphoric acid was deleted by calf intestinal alkaline phosphatase (CIP), then radiolabelled with T4 polynucleotide kinase and γ-32P-ATP. Under the conditions such as pH 7.5 and a 10 mmol/L Mg2+ concentration, TDRz-127 and TDRzl were separately (a 5 μmol/L final concentration) or combinedly (each 2.5μmol/L) mixed with the substrate RNA (200 nmol/L). After denaturation and then renaturation , the reaction systems were incubated in 3T℃, and aliquots were removed to terminate the reaction at intended time points. The cleavage products were separated with 8% denaturated polyacrylamide gel electrophoresis and displayed by autoradiography. Finally, the optical density of each product band was measured with Gel Documentation-Analyzing Systems for calculating the percentages of cleaved HCV 5' -NCR-C. Results After reaction for 15, 30, 45, 60, 75 and 90 min under the adopted conditions, about 8.3%, 16.1%, 24.3%, 26.2%, 29.4% and 31.1% of HCV 5' -NCR-C was cleaved by TDRz-127 respectively; 7.4%, 13.0%, 15.6%, 18.7%, 19.4% and 20.3% by TDRzl; and 15.1%, 29.6%, 37.8%, 39.1%, 41.5%, 42.6% by combining the two TDRzs. Conclusions Cleavage percentage of both TDRz-127 and TDRzl increases with the time, and the effect of combining the two TDRzs is better than that of anyone.
出处
《中华肝脏病杂志》
CAS
CSCD
2003年第3期156-158,共3页
Chinese Journal of Hepatology
