Multiple Buster transposons from hAT superfamily displaying transposition activities in mammal cells

TcBuster, a member of the <i>Buster</i> family within the <i>hAT</i> superfamily, has been engineered into an effective gene transfer tool for gene therapy applications. To diversify the toolkit available for efficient gene delivery, we conducted a bioinformatics analysis, which indicated that some <i>Buster (BT)</i> transposons exhibit signs of recent activity in Actinopterygii and Arthropoda species. Cell-based transposition assays demonstrated that endogenous transposases from <i>Armadillidium nasatum</i> (<i>AnBT</i>), <i>Hyles vespertilio</i> (<i>HvBT</i>), and <i>Lota lota</i> (<i>LlBT</i>) showed 47 %, 44 %, and 39 % transposition activity, respectively, in comparison to that of <i>piggyBac</i> transposons. Conversely, transposases from <i>Carcinoscorpius rotundicauda</i> (<i>CrBT</i>) and <i>Larimichthys crocea</i> (<i>LcBT</i>) presented minimal activity. Further assays confirmed that the 240 bp left and 126 bp right terminal sequences of the <i>AnBT</i> transposon are critical for maintaining transposition activity. In addition, <i>AnBT</i> exhibited the typical overproduction inhibition effect, reaching optimal activity at a 50 ng helper plasmid input, with both minimal (10 ng) and maximal (500 ng) doses of the donor plasmid. Notably, <i>AnBT</i>'s transposition efficiency was 63 % compared to that of <i>piggyBac</i> at peak activity levels. This evidence suggests that <i>AnBT</i> could be a promising alternative gene delivery vector for gene therapy and transgenesis.