摘要
基因沉默是近几年来在转基因植物中发现的一种后生遗传现象。基因沉默大体可以分为两类 :位置效应引起的基因沉默和同源依赖的基因沉默。其中 ,同源依赖的基因沉默又可以分为转录水平的基因沉默和转录后水平的基因沉默。基因沉默的发现使得人们对植物和病毒的相互关系有了一个新的认识。基因沉默研究中所发现的转录后基因沉默现象是植物抵御病毒入侵、保持自身基因组完整性的一种防御机制 ,是植物与病毒共进化的结果。对于沉默产生的机理 ,尤其是转录后基因沉默 ,已经提出不少模型 ,但是都未能较全面地解释基因沉默中出现的各种实验现象。该文现就实验所取得的相关结果、转录后基因沉默机制和植物对病毒防御机制的相互关系 。
Gene silencing is a kind of epigenetic phenomenon discovered in transgenic plants in recent years.Gene silencing can be divided into two types:position effect and homology dependent gene silencing (HdGS).Homology dependent gene silencing (HdGS),which is the generic term for transcriptional gene silencing (TGS),post transcriptional gene silencing (PTGS) and RNA mediated virus resistance (RmVR) have been shown to frequently occur in transgenic plants.Post transcriptional gene silencing (PTGS) is an antiviral defense system of plants,which has led to a new understanding of the relationship between viruses and plants.And it's a co evolution result between plants and viruses.A few hypothesis models have been proposed to elucidate the mechanism of gene silencing,but they could not explain all the phenomena in gene silencing.In this paper,we reviewed the relationship between PTGS and the plants defense mechanism to virus,and proposed a model of gene silencing based on our experiments results.
基金
国家自然科学基金重点项目(3 99890 0 1)
国家"973"(G2 0 0 0 0 162 0 5 )资助项目~~
关键词
基因沉默
转录后基因沉默
病毒
防御机制
gene silencing
post transcriptional gene silencing
virus
defense mechanism
