植物反转录转座子及其在功能基因组学中的应用

高等植物中的反转录转座子是构成植物基因组的重要成分之一.它分病毒家族和非病毒家族两类,病毒家族包括反转录病毒和类似于反转录病毒的非病毒转座子,病毒家族中的反转录转座子可再细分为Ty3-gypsy类和Ty1-copia类;非病毒家族可细分为LINE类和SINE类.正常情况下大部分反转录转座子不具有活性,某些生物或非生物因素胁迫可激活部分反转录转座子转座.反转录转座子自身编码反转录酶进行转录,以"拷贝-粘贴"的转座模式导致基因组扩增和进化.具有活性的反转录转座子通过插入产生新的突变,可作为一种基因标签技术,应用于功能基因组学研究,并成为研究植物基因功能和表达的重要技术平台.本文综述了近几年来在植物反转录转座子方面的研究进展,主要包括植物反转录转座子的结构、特征、活性及其对基因组的影响和它们在功能基因组学中的应用.

Characteristics of Plant Retrotransposons and Their Applications in Functional Genomics

Retrotransposons are mobile genetic elements that make up a large fraction of most eukaryotic genomes. They are particularly abundant in plants, as a principal component of nuclear DNA. Retrotransposons can be divided into two main categories, those with long terminal repeats (LTRs), such as retroviruses and LTR retrotransposons (Ty1-copia type and Ty3-gypsy type), and those lacking such repeats, as long interspersed nuclear elements (LINE type) and short interspersed nuclear elements (SINE type). Most retrotransposons sequences normally show inactive, but some could express under biotic and abiotic stress. Differences observed in plant genomes can be attributed to retroelement amplification leading to genome expansion. So retrotransposons contribute greatly to the genetic diversity and genome size variability of plants. Up to date, active retrotransposons have been introduced into a few plant species. These elements have been used as a powerful tool for studying plant gene functions and expression. In this paper, the progress of plant retrotransposons for recent years is systematically reviewed from the following aspects: structure, charateristics, activation, effection of plant genome and application of fuctional genomics.