昆虫中RNA介导的转座因子

RNA Mediated Transposable Elements in Insects

在昆虫中编码反转录酶的转座因子分为二大类：含长末端重复（ＬＴＲｓ）和不含长末端重复的转座因子．ＬＴＲｓ反转录转座子是具有两侧长正向重复末端序列的片段，中间部分序列包括一个或一个以上的ＯＲＦｓ（开放性阅读框架），其编码转座因子复制和转座所必需的蛋白质；包括ＧｙｐｓｙＴｙ３家族、ＣｏｐｉａＴｙ１家族和Ｐａｏ因子等．不含长末端重复的转座因子有时称为反转座子，能编码反转录酶但缺乏整合酶；包括Ｉ、Ｆ、Ｇ、Ｊｏｃｋｅｙ、Ｄｏｃ和ＨｅｔＡ等因子．

RNA mediated transposable elements that may encode reverse transcriptase are divided into two major groups those containing long terminal repeats(LTRs) and those without them. The former,such as Gypsy Ty3 family,Copia Ty1 family and Pao element,may encode proteins necessary for replication and transposition of the element and usually contain three ORFs. The latter,such as I,F,G,Jockey,Doc and Het A elements,may encode reverse transcriptase but are lack aspartic protease and intergrase. Recent researches about the major families of RNA mediated transposable elements in insects are discussed in this paper.