Rezende-Teixeira P, do Amaral J B, Siviero F, Machado-Santelli G M
Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brasil.
Genet Mol Res. 2012 May 21;11(2):1475-85. doi: 10.4238/2012.May.21.4.
Mobile elements are widely present in eukaryotic genomes. They are repeated DNA segments that are able to move from one locus to another within the genome. They are divided into two main categories, depending on their mechanism of transposition, involving RNA (class I) or DNA (class II) molecules. The mariner-like elements are class II transposons. They encode their own transposase, which is necessary and sufficient for transposition in the absence of host factors. They are flanked by a short inverted terminal repeat and a TA dinucleotide target site, which is duplicated upon insertion. The transposase consists of two domains, an N-terminal inverted terminal repeat binding domain and a C-terminal catalytic domain. We identified a transposable element with molecular characteristics of a mariner-like element in Atta sexdens rubropilosa genome. Identification started from a PCR with degenerate primers and queen genomic DNA templates, with which it was possible to amplify a fragment with mariner transposable-element homology. Phylogenetic analysis demonstrated that this element belongs to the mauritiana subfamily of mariner-like elements and it was named Asmar1. We found that Asmar1 is homologous to a transposon described from another ant, Messor bouvieri. The predicted transposase sequence demonstrated that Asmar1 has a truncated transposase ORF. This study is part of a molecular characterization of mobile elements in the Atta spp genome. Our finding of mariner-like elements in all castes of this ant could be useful to help understand the dynamics of mariner-like element distribution in the Hymenoptera.
可移动元件广泛存在于真核生物基因组中。它们是重复的DNA片段，能够在基因组内从一个位点移动到另一个位点。根据其转座机制，它们分为两大类，涉及RNA（I类）或DNA（II类）分子。类水手元件是II类转座子。它们编码自己的转座酶，在没有宿主因子的情况下，转座酶对于转座是必要且充分的。它们两侧是短的反向末端重复序列和一个TA二核苷酸靶位点，插入时该靶位点会被复制。转座酶由两个结构域组成，一个N端反向末端重复序列结合结构域和一个C端催化结构域。我们在红足切叶蚁基因组中鉴定出一种具有类水手元件分子特征的可移动元件。鉴定工作始于用简并引物和蚁后基因组DNA模板进行的PCR，通过该方法可以扩增出与水手转座元件具有同源性的片段。系统发育分析表明，该元件属于类水手元件的mauritiana亚家族，并将其命名为Asmar1。我们发现Asmar1与另一种蚂蚁布氏收获蚁中描述的转座子同源。预测的转座酶序列表明Asmar1有一个截短的转座酶开放阅读框。本研究是切叶蚁属基因组中可移动元件分子特征研究的一部分。我们在这种蚂蚁的所有品级中都发现了类水手元件，这可能有助于理解膜翅目昆虫中类水手元件分布的动态变化。
