对虾白斑综合征病毒囊膜蛋白VP110 N端结构特征、原核表达及检测

摘要

VP110 is an envelope protein of prawn white spot syndrome virus( WSSV). Similarity analysis found that VP110 possessed homology to oral infection factor PIF2 in insect DNA viruses,and its homologic region located in N-terminal150aa to 600aa. Meanwhile,both of them have a transmembrane region at the leading end of N-terminal. To figure out if VP110 N-terminal conserved region played a crucial role in WSSV infection,N-terminal fraction of vp110 gene(Svp110,450~1 830 bp)was cloned into pET-16b and pGEX-4T1 prokaryotic expression systems. Mo-reover,both BL21(DE3)and Rosetta 2 E. coli expression strains were selected for optimizing the expression condi-tions,to induce VP 110 N-terminal protein(sVP110)to express. The results indicated that recombinant pET-16b-Svp110 can be expressed under the condition of 37 ℃ and 1 mmol/L IPTG but showed lower expression level at 16℃. However,recombinant pGEX-4T1-Svp110 revealed higher expression level at 16 ℃. Furthermore,the expression level of Rosetta 2 strain was higher than that of BL21(DE3). This result showed that Rosetta 2 strain was more suit-able for WSSV structural protein expression. Moreover,the expression of VP110 in different vector was affected by temperature. And the expression of VP110 N-terminal protein lay a foundation for VP110 functional study to come.%VP110为对虾白斑综合征病毒（ White Spot Syndrome Virus，WSSV）的囊膜蛋白。相似性分析发现， VP110与昆虫DNA病毒经口感染关键因子PIF2具同源性，且同源区主要位于N端150~600aa。同时两者均在N端前端含一个跨膜区。为了研究VP110 N端保守区的功能，将vp110 N端基因（ Svp110，450~1830 bp）克隆至pET-16b及pGEX-4T1原核表达载体中，同时分别在大肠埃希菌BL21（DE3）、Rosetta 2菌株中优化表达条件，诱导VP110 N端蛋白（ sVP110）表达。实验结果表明，重组质粒pET-16b-Svp110在37℃1 mmol/L IPTG条件下可得到表达，但16℃下表达量很低。而重组质粒pGEX-4T1-Svp110则在16℃下得到较高表达。同时， Rosetta 2菌株的表达量高于BL21（DE3）。该研究表明Rosetta 2菌株更适合作为WSSV结构蛋白的表达，同时VP110在不同载体中的表达受温度的影响。VP110 N端蛋白的表达为VP110的功能研究打下了基础。