植物 mRNA 可經由原生質絲 (plasmodesmata, PD) 和韌皮部 (phloem) 進行細胞間及長距離運輸以影響植物發育，而 RNA 病毒也可藉由原生質絲和韌皮部運輸病毒 RNA 以完成系統性感染。病毒移動蛋白 (movement protein, MP) 為非序列專一性 RNA 結合蛋白，可將病毒 RNA 運輸至原生質絲以促進病毒 RNA 運輸至鄰近細胞。透過先前 RNA 即時成像系統結果表明菸草嵌紋病毒 (tobacco mosaic virus, TMV) 移動蛋白 (TMV MP) 可與非病毒 RNA 結合並帶至原生質絲。然而是否病毒移動蛋白可促進非病毒內源性 mRNAs運輸至鄰近細胞仍未清楚。為了檢驗此一假設，我們以綠色螢光蛋白 (green fluorescent protein, GFP) 標定TMV MP (TMVMP-GFP) 轉基因至阿拉伯芥中，轉殖株具有早開花之表現型且TMV MP-GFP蛋白質累積。進一步轉殖 SUC2 promoter 驅動紅色螢光蛋白 (red fluorescent protein, RFP) 於野生型 (Columbia, Col) 和 TMV MP-GFP 轉殖株中觀測mRNAs 之運輸。藉由嫁接結果顯示在 TMV MP-GFP 嫁接嵌合體中RFP 及TMV MP mRNAs可進行長距離運輸。此外，將TMV MP-GFP轉殖至 CHOLINE TRANSPORTER-LIKE 1 (CHER1) 突變株，為一種囊泡運輸和原生質絲突變株。TMV MP-GFP/cher1-4具有晚開花之表現型，且有 TMV MP mRNA表現但無蛋白質累積。綜合以上，我們提出 TMV MP-GFP 可帶非移動性mRNAs 經由囊泡運輸至原生質絲後，再帶至韌皮部進行長距離運輸。;Plant mRNA can move cell-to-cell and long-distance via plasmodesmata (PD) and phloem to influence plant development, RNA viruses can also transport viral RNA by PD and phloem to complete systemic infection. Viral movement protein (MP), which is a non-sequence-specific RNA binding protein, target viral RNA to plasmodesmata (PD), in turn promoting the viral RNA transport to neighboring cells. RNA live imaging system results indicated that tobacco mosaic virus movement protein (TMV MP) can bind non-viral RNA to PD. However, it is still unclear whether the viral movement protein affects non-viral endogenous mRNAs transport to neighboring cells. To test this hypothesis, we used green fluorescent protein (GFP) to label TMV MP (TMVMP-GFP) and transformed into Arabidopsis. The transformant shows an early flowering phenotype and TMV MP-GFP protein accumulation. Further we transformed SUC2 promoter fusion red fluorescent protein (RFP) into wildtype and TMV MP-GFP to observe the mRNA mobilization in Arabidopsis. The grafting assay suggested that RFP and TMV MP mRNAs can move long-distance in TMV MP-GFP grafting chimera. In addition, we induced TMV MP-GFP into CHOLINE TRANSPORTER-LIKE 1 (CHER1) mutant, which is a vesicles transport and PD mutant. TMV MP-GFP/cher1-4 showed a late flowering phenotype, and TMV MP mRNA expression but no protein accumulation. Taken together, we propose that TMV MP-GFP can transport non-mobile mRNAs via vesicles to PD, and then transport into phloem for long-distance transport.
