N-terminal of L protein of vesicular stomatitis virus contains a new signal sequence

The L protein (241kD) of vesicular stomatitis virus (VSV) is the most important snbnnit of the replication complex. The existence of specific localization signal in the L protein was investigated by making recombinant constructs expressing truncated mutants of the L protein fused to green fluorescent protein (GFP) in transient transfection assays. The chimeric genes encoding varied N-terminal of L and GFP gene were put under the control of T7 promoter or CMV promoter. The fusion proteins were transiently expressed in BHK-21, COS-7, CHO or Hep G2 cells. When more than 120 residues were deleted or only 96 residues were kept on the N-terminal, the fusion proteins were shown to be distributed throughout the cells, cytoplasm and nucleus under the confocal microscope. However, other chimeric proteins with 120 or more amino acids were dotted and distributed in the perinuclear regions. And the fusion protein with 96—120 aa has the similar distribution. A thirteen-residue peptide QGYSFLHEVDKEA (108—120) was identified as localization signal, whose function would be absolutely distributed with the deficiency of D or V. Our results show that there is an independent localizing signal in N-terminal domain of L protein of VSV and this functional signal is conserved in different cell lines.     

番木瓜环斑病毒复制酶基因的克隆和序列分析

用ＲＴ－ＰＣＲ技术从ＰＲＶ－ＡＬ中分离到复制酶（ＲＰ）基因，将基因克隆进载体ｐＵＣ１８，用双脱氧链终止法测定了基因序列，表明其全长为１６０２ｂｐ，与国内外报道的ＨＡ５－１、ＹＫ和Ｓｍ的ＲＰ基因相比，同源性分别达８２．８０％，９５．０７％和９１．８３％．     

The pathogenicity on legumes of Cucumber mosaic virus was determined by 243 nucleotides on 2a polymerase gene of viral RNA2

We had isolated and identified two Cucumber mosaic virus (CMV) isolates, the CMV red bean (CMV-RB) isolate and the CMV pea (CMV-P1) isolate. CMV-RB induces necrotic local lesions on inoculated leaves of broad bean, pea, cowpea and bean, and could not infect these hosts systemically. However, CMV-P1 was able to infect these legumes systemically. To study the difference of pathogenicity on the legumes induced by these two CMV isolates, the full-length infectious cDNA clones of CMV-Fny, which induced similar symptoms as CMV-RB in the four legumes, were used. The 243 nucleotides fragment, which encodes highly conserved GDD amino acid motif on 2a replicase gene of CMV-Fny RNA2, was replaced with that of CMV-P1. The constructed chimeric virus FP could infect these legumes systemically. The exchange of this region changes the virus symptoms on the legumes, indicating that this 243 nucleotides fragment has major effect on pathogenicity of CMV on the legumes.     

复制酶基因介导的抗病毒烟草植株的研究

将构建的携带烟草花叶病毒（ＴＭＶ）５４ＫＤ蛋白基因及黄瓜花叶病毒（ＣＭＶ）３’端缺失０．９Ｋｂ的１．６Ｋｂ片断复制酶基因植物表达载体ｐＢＩＣＴ，导入根癌农杆菌３１１ＳＥ系，用叶圆盘法转化烟草，在含有卡那霉素的选择性培养基上诱导生芽、生根，得到２８株成活苗．移入大田后，随机挑选４．株植物，提取植物总ＤＮＡ，经ＰＣＲ扩增、Ｓｏｒｔｈｅｒｎ杂交检测，结果４株植物中都有复制酶基因的整合，而未经转化的对照组植物则没有．转基因植株在大田试验中表现了良好的抗烟草花叶病毒及黄瓜花叶病毒能力．     

The pathogenicity on legumes of Cucumber mosaic virus was determined by 243 nucleotides on 2a polymerase gene of viral RNA2

We had isolated and identified two Cucumber mosaic virus (CMV) isolates, the CMV red bean (CMV-RB)isolate and the CMV pea (CMV-P1) isolate. CMV-RBinduces necrotic local lesions on inoculated leaves of broad bean, pea, cowpea and bean, and could not infect these hosts systemically. However, CMV-P1 was able to infect these legumes systemically. To study the difference of pathogenicity. on the legumes induced by these two CMV isolates, the full-length infectious cDNA clones of CMV-Fny, which induced similar symptoms as CMV-RB in the four legumes,were used. The 243 nucleotides fragment, which encodes highly conserved GDD amino acid motif on 2a replicase gene of CMV-Fny RNA2, was replaced with that of CMV-P1. The constructed chimeric virus FP could infect these legumes systemically. The exchange of this region changes the virus symptoms on the legumes, indicating that this 243 nucleotides fragment has major effect on pathogenicity of CMV on the legumes.``     

苜蓿花叶病毒RNA_23′端cDNA转基因烟草及其抗病性研究

将本室克隆的编码复制酶基因3′端约1/2序列及其3′端非编码区的苜蓿花叶病毒中国分离株(AlMV-Ch)RNA23′端cDNA,重组到植物表达载体pROKII中,通过致瘤农杆菌(A-grobacteriumtumefaciens)介导,以叶圆片为转化材料,转化普通烟草,并获得了转基因植株.经卡那霉素抗性选择、PCR检测目的基因证明AlMVRNA23′端基因已整合到转基因烟草的基因组DNA中.转基因植物的攻毒试验表明转基因植株对苜蓿花叶病毒产生高水平的抗性.     

苜蓿花叶病毒复制酶基因全长cDNA植物表达载体的构建

将苜蓿花叶病毒中国分离株（Alfalfa mosaic virus Chinese isolate，AlMV-Ch）的复制酶P2亚基（90KD蛋白）基因的全长cDNA构建到植物表达载体pROK Ⅱ中，得到重组植物表达载体pAlMV-FL．     

苜蓿花叶病毒复制酶基因全长cDNA植物表达载体的构建和对烟草的转化

将苜蓿花叶病毒中国分离株(Alfalfa mosaic virus Chinese isolate，A1MV-Ch)的复制酶P2亚基(90 kD蛋白)基因的全长cDNA构建到植物表达载体pROKⅡ中，得到重组植物表达载体pAIMV-FL．用三亲融合法导入农杆菌LBA4404，并转化烟草，经PCR检测，获得了含全长cDNA的转基因烟草植抹．     

苜蓿花叶病毒复制酶基因的克隆、序列分析及其植物表达载体的构建

以侵染苜蓿的苜蓿花叶病毒中国分离株(Alfalfa mosaic virus Chinese isolate，A1MV—Ch)RNA2为模板，利用人工合成的特异性引物，进行反转录及PCR扩增，分两段分别扩增了复制酶基因的5′端1．32kb和3′端及其非编码区的1．23kb cDNA序列．用限制性内切酶切割PCR产物后，与pUCl9重组，转化大肠杆菌DH5α，筛选重组质粒，用限制性内切酶分析及PCR鉴定，得到分别含有5′端序列和3′端序列的重组质粒。已由上述两种重组质粒构建了含有完整复制酶基因的重组质粒．进行了全序列测定，并与国外报道的A1MV-425株系的相应序列相比较，其复制酶基因编码区核苷酸序列同源性达97．8％，推测的氨基酸序列的同源性达97．6％，3′端非编码区核苷酸序列同源性为98．2％．并将全长复制酶基因与植物表达载体pROKⅡ重组，得植物转化载体pAlMV—FL．     

针对马铃薯卷叶病毒复制酶基因负链的突变核酶的克隆及体外转录

根据特异性切割马铃薯卷叶病毒中国分离株 ( PLRV-Ch)复制酶基因负链 RNA的锤头状核酶 ,设计、合成了编码与其相应的突变核酶的 c DNA,并克隆到质粒 p GEM-4 Z中 ,经序列分析及体外转录表明得到完整的突变核酶基因重组质粒 ,从而为突变核酶的转基因及进一步研究核酶在转基因马铃薯中表达引起的抗性及机理创造了条件