狂犬病病毒突变株rRC-HL(GX074P1M1)的构建及其生物学特性

Construction of rabies virus mutant strain rRC-HL (GX074P1M1)and its biological characteristics

  • 摘要: 【目的】 构建狂犬病病毒(RABV)突变株rRC-HL(GX074P1M1)并探究其生物学特性,分析磷蛋白(P)与基质蛋白(M)部分区域联合突变对RABV转录和复制水平的影响,以了解RABV的致病机制,为靶点预防与治疗提供理论依据。【方法】 通过反向遗传学技术,将RABV街毒株GX074的P蛋白P1区域(第48~78位氨基酸)与M蛋白M1区域(第1~22位氨基酸)联合嵌入弱毒株RC-HL相应位置,通过间接免疫荧光试验(IFA)、实时荧光定量PCR和Western blotting分别测定突变毒株和对照毒株[RC-HL、GX074、rRC-HL(GX074PM)和CVS-11]感染细胞BSR/T7-9后的病毒滴度与核蛋白(N)基因、P基因和M基因及其蛋白相对表达量。【结果】 通过病毒拯救成功获得突变毒株rRC-HL(GX074P1M1)。病毒多步生长曲线测定结果显示,感染BSR/T7-9细胞24~96 h内,突变毒株rRC-HL(GX074P1M1)的病毒滴度均高于亲本毒株RC-HL和GX074。通过实时荧光定量PCR检测发现,突变毒株rRC-HL(GX074P1M1)在感染24和48 h时,N基因、P基因和M基因的相对表达量均显著(P<0.05)或极显著(P<0.01,下同)高于亲本毒株RC-HL和GX074。Western blotting检测结果显示,在感染24 h时,与亲本毒株RC-HL相比,突变毒株rRC-HL(GX074P1M1)的N蛋白、P蛋白和M蛋白相对表达量均小幅上升;在感染48 h时,突变毒株rRC-HL(GX074P1M1)的N蛋白、P蛋白和M蛋白相对表达量均极显著高于亲本毒株RC-HL与GX074。【结论】 RABV街毒株GX074的P1和M1区域联合嵌入弱毒株RC-HL获得的突变毒株rRC-HL(GX074P1M1)复制及转录水平比亲本毒株高,在细胞内具有更强的增殖能力,表明街毒株GX074的P蛋白P1区域和M蛋白M1区域在促进病毒转录及复制中发挥协同作用。

     

    Abstract: 【Objective】 The objective of this study was to construct the rabies virus(RABV)mutant strain rRC-HL (GX074P1M1)and investigate its biological characteristics,analyzed the impact of combined mutations in the phosphoprotein(P)and matrix protein(M)regions on RABV transcription and replication levels,in order to study the pathogenic mechanisms of RABV and provide theoretical basis for targeted prevention and treatment. 【Method】 Using reverse genetics technology,the P protein P1 region(amino acids at positions 48-78)and M protein M1 region(amino acids at positions 1-22)of the RABV street strain GX074 were co-embedded into the corresponding positions of the attenuated strain RC-HL. The virus titers and the relative expression levels of the nucleoprotein(N)gene,P gene,and M gene,as well as their proteins were determined for the mutant strain and control strains[RC-HL,GX074,rRC-HL(GX074PM), and CVS-11]after infection of BSR/T7-9 cells using indirect immunofluorescence assay(IFA),real-time fluorescence quantitative PCR and Western blotting. 【Result】 The mutant strain rRC-HL(GX074P1M1)was successfully obtained through virus rescue. Multi-step virus growth curve assays showed that the virus titer of the mutant strain rRC-HL (GX074P1M1)was higher than that of the parental strains RC-HL and GX074 within 24-96 h post infection of BSR/T7-9 cells. Real-time fluorescence quantitative PCR revealed that the relative expression levels of the N gene,P gene and M gene of the mutant strain rRC-HL(GX074P1M1)were significantly(P<0.05)or extremely significantly(P<0.01,the same below)higher than those of the parental strains RC-HL and GX074 at 24 and 48 h post infection. Western blotting results indicated that at 24 h post infection,the relative expression levels of N protein,P protein and M proteins in the mutant strain rRC-HL(GX074P1M1)were slightly higher than those in the parental strain RC-HL. At 48 h post infection, the relative expression levels of N protein,P protein and M proteins in the mutant strain rRC-HL(GX074P1M1)were extremely significantly higher than those in the parental strains RC-HL and GX074. 【Conclusion】 The mutant strain rRC-HL (GX074P1M1),obtained by co-embedding the P1 and M1 regions of the RABV street strain GX074 into the attenuated strain RC-HL,exhibits higher replication and transcription levels than the parental strains,indicating a stronger intracellular proliferation capability. This suggests that the P protein P1 region and M protein M1 region of the street strain GX074 play synergistic effects in promoting viral transcription and replication.

     

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