Yang Guojun, Nagel Dawn Holligan, Feschotte Cédric, Hancock C Nathan, Wessler Susan R
Department of Plant Biology, University of Georgia, Athens, GA 30602, USA.
Science. 2009 Sep 11;325(5946):1391-4. doi: 10.1126/science.1175688.
Miniature inverted repeat transposable elements (MITEs) are widespread in eukaryotic genomes, where they can attain high copy numbers despite a lack of coding capacity. However, little is known about how they originate and amplify. We performed a genome-wide screen of functional interactions between Stowaway MITEs and potential transposases in the rice genome and identified a transpositionally active MITE that possesses key properties that enhance transposition. Although not directly related to its autonomous element, the MITE has less affinity for the transposase than does the autonomous element but lacks a motif repressing transposition in the autonomous element. The MITE contains internal sequences that enhance transposition. These findings suggest that MITEs achieve high transposition activity by scavenging transposases encoded by distantly related and self-restrained autonomous elements.
微型反向重复转座元件（MITEs）广泛存在于真核生物基因组中，尽管它们缺乏编码能力，但仍能达到很高的拷贝数。然而，关于它们如何起源和扩增的了解却很少。我们对水稻基因组中Stowaway MITEs与潜在转座酶之间的功能相互作用进行了全基因组筛选，并鉴定出一个具有增强转座关键特性的转座活性MITE。尽管该MITE与其自主元件没有直接关系，但它对转座酶的亲和力比自主元件低，且缺乏自主元件中抑制转座的基序。该MITE包含增强转座的内部序列。这些发现表明，MITEs通过利用远缘相关且自我抑制的自主元件编码的转座酶来实现高转座活性。
