O型口蹄疫病毒非结构蛋白2C突变毒株的构建及其生物学特性分析OA

To elucidate how the T135I substitution in the nonstructural protein 2C affects the ca-pacity of foot-and-mouth disease virus(FMDV)serotype O to survive intracellularly during the estab-lishment of persistent infection,a recombinant FMDV harboring the T135I mutation in the 2C protein was constructed using reverse genetics and its replicative fitness was analyzed through growth curve analysis,real-time quantitative PCR,and Western-blotting for phenotypic characterization.The mutant was successfully rescued and remained genetically stable.It exhibited significantly higher viral titres,as well as increased genomic and protein expression,in BHK-21 cells compared with the parental strain(P<0.05),whereas these parameters were markedly reduced in MDBK cells(P<0.05).Collective-ly,these data identify residue 2C-T135 as a critical molecular determinant of FMDV adaptation to the MDBK cellular environment and highlight the context-dependent functionality of this locus.The gener-ated mutant provides a robust platform for further dissecting FMDV persistent infection mechanisms and virus-host adaptive interplay.