马赛病毒是继拟菌病毒之后被发现的第2类阿米巴巨型病毒，拥有庞大的双链DNA基因组。基因组分析显示，马赛病毒上海株(Mar-SH2016)编码4种潜在翻译因子。其中，ORF314基因与真核翻译起始因子eIF2/eIF5的氨基酸同源性约为60%，但其在马赛病毒复制中的作用还有待揭示。本研究设计了3对靶向Mar-SH2016 ORF314基因的siRNA，通过转染宿主卡氏棘阿米巴细胞，分析siRNA对ORF314基因表达水平和病毒复制的影响。用荧光标记的siRNA转染卡氏棘阿米巴细胞，结果显示约1/3阿米巴细胞成功转染。实时定量聚合酶链反应(real-time quantitative polymerase chain reaction，RT-qPCR)和蛋白免疫印迹实验证实，在Mar-SH2016感染宿主的过程中siRNA能使ORF314基因表达水平显著下降。siRNA干扰后病毒毒力测定结果显示，Mar-SH2016的毒力降低约30%(P<0.01)。结果表明，降低ORF314基因的表达水平能显著抑制Mar-SH2016复制。

Marseillevirus is a type of giant virus that infects Acanthamoeba castellanii. Like other giant viruses, Marseillevirus has a large genome and encodes several potential protein translation factors. Genomic analysis revealed that Marseillevirus Shanghai strain (Mar-SH2016) encodes four potential translation factors, one of which, ORF314 gene, has a high homology (60%) with the eukaryotic translation initiation factor eIF2/eIF5. But the role of ORF314 in virus replication remains to be revealed. In this study, three pairs of small interfering RNA (siRNAs) were designed to target ORF314 gene. Transfection of amoeba cells with fluorescence-labeled siRNAs showed that about one third of the Acanthamoeba castellanii cells were successfully transfected. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting confirmed that the siRNAs decreased the mRNA level of ORF314, and the results of virus titration showed that the level of virus replication decreased significantly (P<0.01). It is indicated that the potential translation initiation factor ORF314 of Mar-SH2016 has a role in the replication of the virus.