【摘要】 转录后基因沉默现象广泛存在于植物、动物和真菌中。在植物中转录后基因沉默现象是对外来病毒入侵的一种防御机制。植物病毒既是转录后基因沉默的起始物、靶目标,又是编码抑制转录后基因沉默的蛋白。已经发现3种病毒抑制子作用于转录后基因沉默的不同阶段:烟草蚀刻病毒蛋白(HC-Pro)作用于转录后基因沉默的持续阶段,产生25 nt小RNA的上游和产生沉默信号的下游区域;马铃薯X病毒蛋白(P25)和黄瓜花叶病毒蛋白(CMV2b)作用于转录后基因沉默的信号阶段。更多还原

【Abstract】 Post transcriptional gene silencing (PTGS) has been found to occur in plants, animals and fungi. PTGS in plants acts naturally as a natural antiviral defense because plant viruses are both initiators and targets of PTGS and encode proteins that suppress PTGS. Three types of viral silencing suppressors targeting different steps of PTGS have been identified to date. HC-Pro targets a maintenance step of the PTGS pathway that is upstream to the production of the 25 nt RNAs but downstream to the signal production. Both P25 of potato virus X and the cucumber mosaic virus 2b protein (CMV2b) target the signaling step of the pathway.更多还原