Ben Amara Wiem, Djebbi Salma, Khemakhem Maha Mezghani
Laboratory of Biochemistry and Biotechnology (LR01ES05), Faculty of Sciences of Tunis, University of Tunis El Manar, 1068, Tunis, Tunisia.
Biochem Genet. 2024 Aug 8. doi: 10.1007/s10528-024-10898-z.
Tc1/mariner elements are ubiquitous in eukaryotic genomes including insects. They are diverse and divided into families and sub-families. The DD34D family including mauritiana and irritans subfamilies have already been identified in two closely related species of Cecidomyiids M. destructor and M. hordei. In the current study the de novo and similarity-based methods allowed the identification for the first time of seven consensuses in M. destructor and two consensuses in M. hordei belonging to DD41D family whereas the in vitro method allowed the amplification of two and three elements in these two species respectively. Most of identified elements accumulated different mutations and long deletions spanning the N-terminal region of the transposase. Phylogenetic analyses showed that the DD41D elements were clustered in two groups belonging to rosa and Long-TIR subfamilies. The age estimation of the last transposition events of the identified Tc1/mariner elements in M. destructor showed different evolutionary histories. Indeed, irritans elements have oscillated between periods of silencing and reappearance while rosa and mauritiana elements have shown regular activity with large recent bursts. The study of insertion sites showed that they are mostly intronic and that some recently transposed elements occurred in genes linked to putative DNA-binding domains and enzymes involved in metabolic chains. Thus, this study gave evidence of the existence of DD41D family in two Mayetiola species and an insight on their evolutionary history.
Tc1/水手元件在包括昆虫在内的真核生物基因组中普遍存在。它们种类多样，可分为不同的家族和亚家族。包括mauritiana和irritans亚家族在内的DD34D家族已在两种密切相关的瘿蚊科物种——毁灭麦瘿蚊和大麦麦瘿蚊中被鉴定出来。在本研究中，从头测序法和基于相似性的方法首次在毁灭麦瘿蚊中鉴定出7个共有序列，在大麦麦瘿蚊中鉴定出2个属于DD41D家族的共有序列，而体外方法分别在这两个物种中扩增出2个和3个元件。大多数已鉴定的元件积累了不同的突变以及跨越转座酶N端区域的长片段缺失。系统发育分析表明，DD41D元件聚为两组，分别属于rosa和Long-TIR亚家族。对毁灭麦瘿蚊中已鉴定的Tc1/水手元件最后一次转座事件的年代估计显示出不同的进化历史。实际上，irritans元件在沉默期和重现期之间波动，而rosa和mauritiana元件则表现出近期有大量爆发的规律活性。插入位点的研究表明，它们大多位于内含子中，并且一些最近转座的元件出现在与假定的DNA结合结构域和参与代谢链的酶相关的基因中。因此，本研究证明了DD41D家族在两种麦瘿蚊物种中的存在，并对它们的进化历史有了一定了解。
