中文摘要：

病毒和宿主之间的密码子使用频率差异是病毒在宿主中生存的重要调控机制之一。利用生物学软件Editseq和RSCU算法统计病毒STSV2及其宿主Sulfolobussolfataricus P2中的6个不同基因的遗传密码偏嗜性，并对病毒STSV2的dUTPase在大肠杆菌BL21和Rosetta中分别进行外源表达并分析其差异。结果表明，病毒STSV2密码子的偏嗜性总体与其宿主菌P2相似，STSV2基因组的不同蛋白编码基因的密码子偏嗜性有区别，病毒和宿主的相似蛋白编码序列密码子偏嗜性也有差异。分别以BL21（DE31和Rosetta（DE3）为宿主表达STSV2的dUTPase基因显示，以BL21fDE3）为宿主时表达量大于以Rosetta（DE3）为宿主时目的蛋白表达量，进一步说明了病毒STSV2的密码子的偏嗜性对其蛋白的外源表达影响。

英文摘要：

The difference in codon usage frequency between viruses and hosts is one of the important regu- latory mechanisms for the viruses to survive in their hosts. Software Editseq and the RSCU algorithm were used to analyze genetic code usage bias of six different analogous genes of virus STSV2 and its host Sul- folobussolfataricus P2, which was further tested by the expression of a STSV2 dUTPase gene in E.coli BL21 and Rosetta, respectively. The results showed that STSV2 had similar tropism of genetic codon usage bias to its host bacteria P2, but there was slightly difference between STSV2 genes and between analogous genes of STSV2 and P2. Furthermore, the expression of STSV2 dUTPase gene showed that the yield of target protein expressed in host BL21 （DE3） was significantly higher than that in Rosetta （DE3）, which further demonstrated that the codon usage bias of virus STSV2 affected the heterologous expression of its proteins in different hosts.