马铃薯Y病毒属病毒6K2蛋白叶绿体定位的机制解析OA北大核心CSTPCD

[Objective]This study aims to identify the structural domains that determine the chloroplast localization of the 6K2 protein in potyviruses.[Method]The 6K2 protein was segmented into three structural domains:an N-terminal domain,a transmembrane domain,and a C-terminal domain.The N-segment structural domain,the transmembrane structural domain,and the C-segment structural do-main of the 6K2 protein were deletion mutated,respectively.We constructed six mutants:6K2PVYΔN,6K2PVYΔC,6K2PVYΔNΔC,6K2TuMVΔN,6K2TuMVΔC,and 6K2TuMVΔNΔC.Mutations targeting the GxxxG motifs within the transmembrane regions of 6K2PVY and 6K2TuMV led to the creation of 6K2PVY GV and 6K2TuMV GV mutants.Subsequently,we examined the subcellular localization of these distinct 6K2-RFP mutants using laser confocal microscopy.Different domains of 6K2 protein encoded by PVY and TuMV were re-combined,and recombinant proteins 6K2PPT,6K2PTT,6K2TPT,6K2TTP,6K2TPP,6K2PTP were con-structed.The subcellular localization of different 6K2-RFP recombinant proteins was then observed.[Result]6K2TuMV,along with mutants 6K2TuMVΔN,6K2TuMVΔC,6K2TuMVΔNΔC,6K2PVYΔC,6K2PVYΔNΔC,and recombinant proteins 6K2PPT,6K2PTT,and 6K2TPT,were localized to chloroplasts.In contrast,the localization of 6K2PVY,mutant 6K2PVYΔN,and recombinant proteins 6K2TTP,6K2TPP,and 6K2PTP to chloroplasts was not observed.[Conclusion]The transmembrane domain of potyviruses 6K2 protein de-termines its chloroplast localization.However,the C-terminal structural domain of 6K2PVY has been ob-served to interfere with chloroplast localization.Additionally,differences in the C-terminal domains of 6K2 from PVY and TuMV result in distinct subcellular localizations.