The extra small virus (XSV) is a satellite virus associated with Macrobrachium rosenbergii nodavirus (MrNV) and its genome consists of two overlapping ORFs, CP17 and CP16. Here we demonstrate that CP16 is expresse...The extra small virus (XSV) is a satellite virus associated with Macrobrachium rosenbergii nodavirus (MrNV) and its genome consists of two overlapping ORFs, CP17 and CP16. Here we demonstrate that CP16 is expressed from the second AUG of the CP17 gene and is not a proteinase cleavage result of CP17. We further expressed CP17 and several truncated CP17s (in which the N-or C-terminus or both was deleted), respectively, in Escherichia coli. Except for the recombinant plasmid CP17^AC10, all recombinant plasmids expressed soluble protein which assembled into virus-like particles (VLPs), suggesting that the C-terminus is important for VLP formation.展开更多
目的通过改变原噬菌体ms2包膜蛋白RNA包装位点(19碱基的茎环结构)的数量及亲和力,构建新的原核表达系统,探讨表达内含长片段(达到理论上的1900bp)RNA的耐RNase病毒样颗粒的可能性。方法首先设计含HindⅢ和NotⅠ酶切位点的引物,扩...目的通过改变原噬菌体ms2包膜蛋白RNA包装位点(19碱基的茎环结构)的数量及亲和力,构建新的原核表达系统,探讨表达内含长片段(达到理论上的1900bp)RNA的耐RNase病毒样颗粒的可能性。方法首先设计含HindⅢ和NotⅠ酶切位点的引物,扩增ms2包膜蛋白的编码成熟酶蛋白和衣壳蛋白的1700bp序列,并将原来的19mer的包装位点序列改变为C-5变异体(19 bp stem-loop结构中-5位的尿嘧啶改变为胞嘧啶),HindⅢ和NotⅠ酶切后,与用同样酶切的表达载体pET-28(b)相连接,得到重组载体pET-ms2-pac。应用重叠PCR扩增3种病毒的5段嵌合体序列(包括3段SARS-CoV基因、一段HCV基因和一段H5N1基因),并在SARS-CoV3和HCV序列之间插入一个19mer的变异体包装位点序列,在设计引物时,使嵌合体两端含有NotⅠ酶切位点,与NotⅠ酶切的重组载体pET-ms2-pac相连接,构建得到具有2个变异包装位点的表达载体pET-ms2-3V。同时构建3种对照重组表达载体,分别测定N-P3V-pET-P、N-P3V-pET-C、P-3V-pET-P和pET-ms2-3 V 4种重组表达质粒表达产物的260nm吸光度(A260)值,根据公式A260=0.125mg/ml计算4种表达产物的表达效率。结果成功构建了4种原核表达载体:pET-ms2-3V、P-3V-pET-P、N-P3V-pET-P和N-P3V-pET-C。pET-ms2-3V和P-3V-pET-P经原核表达后得到含全长为1891的5段嵌合体RNA的病毒样颗粒;N-P3V-pET-P、N-P3V-pET-C其原核表达产物病毒样颗粒中仅包装了1200bp的目的嵌合体RNA。N-P3V-pET-P、N-P3V-pET-C、P-3V-pET-P和pET-ms2-3V的表达效率分别为0.23、0.35、0.35和0.51mg/ml。N-P3V-pET-C比N-P3V-pET-P表达效率高52%,而pET-ms2-3V比P-3V-pET-P表达效率高38%。所包装的RNA具有耐RNase和DNase消化的特性以及良好的不同温度条件下的稳定性。结论通过改变噬菌体ms2 RNA包装位点(19碱基的茎环结构)的数量,可构建能表达内含达到理论上的约1900bp外源RNA的耐RNase病毒样颗粒的原核表达载体平台。通过应用包装位点的变异体C-变异体,可以增加病毒样颗粒的表达效率。展开更多
基金National Natural Science Foundation of China (30370057).
文摘The extra small virus (XSV) is a satellite virus associated with Macrobrachium rosenbergii nodavirus (MrNV) and its genome consists of two overlapping ORFs, CP17 and CP16. Here we demonstrate that CP16 is expressed from the second AUG of the CP17 gene and is not a proteinase cleavage result of CP17. We further expressed CP17 and several truncated CP17s (in which the N-or C-terminus or both was deleted), respectively, in Escherichia coli. Except for the recombinant plasmid CP17^AC10, all recombinant plasmids expressed soluble protein which assembled into virus-like particles (VLPs), suggesting that the C-terminus is important for VLP formation.
文摘目的通过改变原噬菌体ms2包膜蛋白RNA包装位点(19碱基的茎环结构)的数量及亲和力,构建新的原核表达系统,探讨表达内含长片段(达到理论上的1900bp)RNA的耐RNase病毒样颗粒的可能性。方法首先设计含HindⅢ和NotⅠ酶切位点的引物,扩增ms2包膜蛋白的编码成熟酶蛋白和衣壳蛋白的1700bp序列,并将原来的19mer的包装位点序列改变为C-5变异体(19 bp stem-loop结构中-5位的尿嘧啶改变为胞嘧啶),HindⅢ和NotⅠ酶切后,与用同样酶切的表达载体pET-28(b)相连接,得到重组载体pET-ms2-pac。应用重叠PCR扩增3种病毒的5段嵌合体序列(包括3段SARS-CoV基因、一段HCV基因和一段H5N1基因),并在SARS-CoV3和HCV序列之间插入一个19mer的变异体包装位点序列,在设计引物时,使嵌合体两端含有NotⅠ酶切位点,与NotⅠ酶切的重组载体pET-ms2-pac相连接,构建得到具有2个变异包装位点的表达载体pET-ms2-3V。同时构建3种对照重组表达载体,分别测定N-P3V-pET-P、N-P3V-pET-C、P-3V-pET-P和pET-ms2-3 V 4种重组表达质粒表达产物的260nm吸光度(A260)值,根据公式A260=0.125mg/ml计算4种表达产物的表达效率。结果成功构建了4种原核表达载体:pET-ms2-3V、P-3V-pET-P、N-P3V-pET-P和N-P3V-pET-C。pET-ms2-3V和P-3V-pET-P经原核表达后得到含全长为1891的5段嵌合体RNA的病毒样颗粒;N-P3V-pET-P、N-P3V-pET-C其原核表达产物病毒样颗粒中仅包装了1200bp的目的嵌合体RNA。N-P3V-pET-P、N-P3V-pET-C、P-3V-pET-P和pET-ms2-3V的表达效率分别为0.23、0.35、0.35和0.51mg/ml。N-P3V-pET-C比N-P3V-pET-P表达效率高52%,而pET-ms2-3V比P-3V-pET-P表达效率高38%。所包装的RNA具有耐RNase和DNase消化的特性以及良好的不同温度条件下的稳定性。结论通过改变噬菌体ms2 RNA包装位点(19碱基的茎环结构)的数量,可构建能表达内含达到理论上的约1900bp外源RNA的耐RNase病毒样颗粒的原核表达载体平台。通过应用包装位点的变异体C-变异体,可以增加病毒样颗粒的表达效率。