二化螟piggyBac类转座子的克隆与分析

Molecular cloning and analysis of piggyBac-like transposon in Chilo suppressalis (Lepidoptera: Pyralidae)

piggyBac转座子是DNA型转座子,广泛分布于生物体内。基于piggyBac转座子超家族成员IFP2开发的转基因工具载体是目前转基因研究中使用最广泛的载体之一,因此piggyBac转座子的研究受到广泛的关注和重视。本文是对二化螟Chilo suppressalis内源性piggyBac类转座子(piggyBac-like element,CsuPLE)的首次报道。克隆的CsuPLE(GenBank登录号:JX392388)全长2537bp,包含一个长1914bp的完整开放阅读框(open reading frame,ORF),编码含637个氨基酸残基的转座酶,转座酶中含有piggyBac家族保守的"DDD-domain"。CsuPLE全长序列具有完全对称的13bp反向末端重复序列(inverted terminal repeats,ITRs)以及非完全对称的21bp内部重复序列(internal repeats,IRs),在二化螟基因组上插入在特征性的"TTAA"靶位点重复(target site duplication,TSD)处。在我国地理跨度很大的不同二化螟种群中均存在结构完整的CsuPLE序列。本研究结果为深入研究piggyBac转座子的结构与功能的关系提供了新的素材,也为评价利用转座子载体系统在二化螟体内进行转基因操作的可行性和安全性提供了重要的理论基础。

piggyBac is a DNA transposon widespread in many organisms. IFP2 is the first piggyBac element found and has been developed as a gene vector most widely used in transgenesis of insects and mammals. Therefore, the study of piggyBac transposons in various organisms has attracted extensive interests and attention. CsuPLE, a novel member of piggyBac transposons, was cloned from Chilo suppressalis in this study with the GenBank accession no. JX392388. The sequence is 2 537 bp in length and contains a single open reading frame （ORF） of 1 914 bp encoding a transposase of 637 amino acids. Within the transposase, there is a conserved DDD-domain. The full-length sequence of CsuPLE contains a pair of perfectly symmetrical 13 bp inverted terminal repeats （ITRs） and a pair of non-completely symmetric 21 bp internal repeats （IRs）. CsuPLE sequence is integrated in the ＂TTAA＂ target site duplication （TSD） of the genome. CsuPLE with similar structure was found in different geographic populations of C. suppressalis from China. This study not only provides insight into the relationship between structure and function of the piggyBac transposon but also sets up a theoretical basis for utilization of the CsuPLE transposon in transgenic research in C. suppressalis.