Rossato Dirleane Ottonelli, Ludwig Adriana, Deprá Maríndia, Loreto Elgion L S, Ruiz Alfredo, Valente Vera L S
Programa de Pós-Graduação em Ecologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.
Genome Biol Evol. 2014 Feb;6(2):352-65. doi: 10.1093/gbe/evu017.
The hAT superfamily comprises a large and diverse array of DNA transposons found in all supergroups of eukaryotes. Here we characterized the Drosophila buzzatii BuT2 element and found that it harbors a five-exon gene encoding a 643-aa putatively functional transposase. A phylogeny built with 85 hAT transposases yielded, in addition to the two major groups already described, Ac and Buster, a third one comprising 20 sequences that includes BuT2, Tip100, hAT-4_BM, and RP-hAT1. This third group is here named Tip. In addition, we studied the phylogenetic distribution and evolution of BuT2 by in silico searches and molecular approaches. Our data revealed BuT2 was, most often, vertically transmitted during the evolution of genus Drosophila being lost independently in several species. Nevertheless, we propose the occurrence of three horizontal transfer events to explain its distribution and conservation among species. Another aspect of BuT2 evolution and life cycle is the presence of short related sequences, which contain similar 5' and 3' regions, including the terminal inverted repeats. These sequences that can be considered as miniature inverted repeat transposable elements probably originated by internal deletion of complete copies and show evidences of recent mobilization.
hAT超家族包含大量多样的DNA转座子，存在于真核生物的所有超群中。在这里，我们对果蝇（Drosophila buzzatii）的BuT2元件进行了表征，发现它含有一个五外显子基因，编码一种643个氨基酸的假定功能性转座酶。用85种hAT转座酶构建的系统发育树，除了已描述的两个主要类群Ac和Buster外，还产生了第三个类群，包含20个序列，其中包括BuT2、Tip100、hAT-4_BM和RP-hAT1。这个第三类群在这里被命名为Tip。此外，我们通过计算机搜索和分子方法研究了BuT2的系统发育分布和进化。我们的数据显示，在果蝇属的进化过程中，BuT2大多是垂直传递的，在几个物种中独立丢失。然而，我们提出发生了三次水平转移事件来解释它在物种间的分布和保守性。BuT2进化和生命周期的另一个方面是存在短的相关序列，这些序列包含相似的5'和3'区域，包括末端反向重复序列。这些可被视为微型反向重复转座元件的序列可能起源于完整拷贝的内部缺失，并显示出近期移动的证据。
