BuT2 Is a Member of the Third Major Group of hAT Transposons and Is Involved in Horizontal Transfer Events in the Genus Drosophila

Abstract

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.

Evolutionary Dynamics of hAT DNA Transposon Families in Saccharomycetaceae

“…S2 , Supplementary Material online), as well as the characteristics of the TIRs and TSDs, confirm that the Roamer and the Rover groups belong to the hAT superfamily, as has already been suggested by the Génolevures consortium ( Souciet et al 2009 ) for Rover and by Rajaei et al (2014) for Roamer . On the basis of the primary sequence of the transposases and TSD sequence conservation, Arensburger et al (2011) , Zhang et al (2013) , and Rossato et al (2014) have divided the hAT superfamily into three groups: Ac , Buster , and Tip . To assign the Rover and the Roamer groups to one of the hAT groups, we compared their transposases with those found in other taxa, including plants, animals, and fungi.…”

“…Bootstrap values are indicated above branches. Transposases are clustered in three groups, as defined by Rossato et al (2014) . However, in our tree, the Buster group is nested within the Tip group with however a moderate support.…”

Characterization of Herves‐like transposable elements (hATs) in Drosophila species and their evolutionary scenario

“…Our results show that Herves -like elements form a monophyletic group within the Ac family of the hAT superfamily (Arensburger et al ., 2011;Rossato et al ., 2014). Until now, these elements have been described only in Diptera insects and, predominantly, in Drosophila.…”

“…They vary in size from 1.5 to 5.0 kb, have short terminal inverted repeats (TIRs) of 5-27 bp in length, and are flanked by 8 bp of a target sequence duplication (TSD) (Arensburger et al ., 2011;Atkinson, 2014). They are divided into three families -Ac , Buster and Tip -based on the sequence of the transposase and differences in target-site selection (Arensburger et al ., 2011;Rossato et al ., 2014). Recently, a fourth family, called hATm , was included in the hAT superfamily (Zhang et al ., 2018).…”

Two hAT transposon genes were transferred from Brassicaceae to broomrapes and are actively expressed in some recipients

“…The hAT superfamily (named after the families: hobo from Drosophila melanogaster , Activator (Ac) from maize, and Tam3 from snapdragon) of class II TEs is widely distributed in fungi, animals, and plants 34 , and phylogenetic analyses suggest that it is ancient, predating the early stages of the divergence of these kingdoms 33 . In animals, hAT has been horizontally transferred among species of Drosophila 35 36 37 , and a novel hAT transposon having the 8-bp TSDs with the characteristic of recent transposition has been found in the silkworm, Bombyx mori , and in a Triatominae vector of the Chagas parasite, Rhodnius prolixus 38 . Prior to this study, no transfer events involving the transposase genes of the hAT superfamily had been reported in plants.…”