Zhang Xiaoyu, Jiang Ning, Feschotte Cédric, Wessler Susan R
Department of Plant Biology, University of Georgia, Athens, GA 30602, USA.
Genetics. 2004 Feb;166(2):971-86. doi: 10.1534/genetics.166.2.971.
Miniature inverted-repeat transposable elements (MITEs) are short, nonautonomous DNA elements that are widespread and abundant in plant genomes. Most of the hundreds of thousands of MITEs identified to date have been divided into two major groups on the basis of shared structural and sequence characteristics: Tourist-like and Stowaway-like. Since MITEs have no coding capacity, they must rely on transposases encoded by other elements. Two active transposons, the maize P Instability Factor (PIF) and the rice Pong element, have recently been implicated as sources of transposase for Tourist-like MITEs. Here we report that PIF- and Pong-like elements are widespread, diverse, and abundant in eukaryotes with hundreds of element-associated transposases found in a variety of plant, animal, and fungal genomes. The availability of virtually the entire rice genome sequence facilitated the identification of all the PIF/Pong-like elements in this organism and permitted a comprehensive analysis of their relationship with Tourist-like MITEs. Taken together, our results indicate that PIF and Pong are founding members of a large eukaryotic transposon superfamily and that members of this superfamily are responsible for the origin and amplification of Tourist-like MITEs.
微型反向重复转座元件（MITEs）是短的非自主DNA元件，在植物基因组中广泛存在且数量众多。在迄今已鉴定出的数十万种MITEs中，大多数已根据共同的结构和序列特征分为两大类：类Tourist元件和类Stowaway元件。由于MITEs没有编码能力，它们必须依赖于其他元件编码的转座酶。最近，两种活跃的转座子，即玉米P不稳定性因子（PIF）和水稻Pong元件，被认为是类Tourist MITEs转座酶的来源。在此我们报告，PIF和类Pong元件在真核生物中广泛存在、种类多样且数量丰富，在各种植物、动物和真菌基因组中发现了数百种与元件相关的转座酶。几乎完整的水稻基因组序列的可得性有助于鉴定该生物体中所有的PIF/类Pong元件，并允许对它们与类Tourist MITEs的关系进行全面分析。综合来看，我们的结果表明，PIF和Pong是一个大型真核转座子超家族的创始成员，并且这个超家族的成员负责类Tourist MITEs的起源和扩增。
