Post-Integration Silencing of piggyBac Transposable Elements in Aedes aegypti

Abstract

The piggyBac transposon, originating in the genome of the Lepidoptera Trichoplusia ni, has a broad host range, making it useful for the development of a number of transposon-based functional genomic technologies including gene vectors, enhancer-, gene- and protein-traps. While capable of being used as a vector for the creation of transgenic insects and insect cell lines, piggyBac has very limited mobility once integrated into the genome of the yellow fever mosquito, Aedes aegypti. A transgenic Aedes aegypti cell line (AagPB8) was created containing three integrated piggyBac elements and the remobilization potential of the elements was tested. The integrated piggyBac elements in AagPB8 were transpositionally silent in the presence of functional transposase, which was shown to be capable of catalyzing the movement of plasmid-borne piggyBac elements in the same cells. The structural integrity of one of the integrated elements along with the quality of element-flanking DNA, which is known to influence transposition rates, were tested in D. melanogaster. The element was found to be structurally intact, capable of transposition and excision in the soma and germ-line of Drosophila melanogaster, and in a DNA sequence context highly conducive to element movement in Drosophila melanogaster. These data show that transpositional silencing of integrated piggyBac elements in the genome of Aedes aegypti appears to be a function of higher scale genome organization or perhaps epigenetic factors, and not due to structural defects or suboptimal integration sites.

The sex locus is tightly linked to factors conferring sex-specific lethal effects in the mosquito Aedes aegypti

“…Integrity of the transgene and its contiguity with genomic flanks was confirmed by PCR ( Figure 1c). Unlike in other dipterans, piggyBac transposons integrated into the A. aegypti genome may not be able to remobilize (Palavesam et al, 2013). Fortuitous truncation of the 3′ arm only strengthens that notion; it made the insertion highly stable, because remobilization of piggyBac would require both arms intact (Li et al, 2001).…”

nanos-Driven expression of piggyBac transposase induces mobilization of a synthetic autonomous transposon in the malaria vector mosquito, Anopheles stephensi

“…The As28 + transgenic line contained four transposase gene copies, whereas the 3.8nanos-attP44C lines had only one, and increased transposase abundance could explain the higher frequency of construct self-mobilization. However, the piggyBac element does not mobilize in Ae aegypti , even in the presence of functional transposase ( Palavesam et al, 2013 ; Sethuraman et al, 2007 ). Furthermore, piggyBac element mobilization in D. melanogaster has been attributed to genomic context, not transposase abundance, while no genomic context has been identified that supports remobilization in Ae.…”

“…Furthermore, piggyBac element mobilization in D. melanogaster has been attributed to genomic context, not transposase abundance, while no genomic context has been identified that supports remobilization in Ae. aegypti ( Esnault et al, 2011 ; Palavesam et al, 2013 ; Sethuraman et al, 2007 ).…”

Control of Mosquito-Borne Infectious Diseases: Sex and Gene Drive

“…Subsequent work showed that P was capable of driving itself [55] and an additional cargo gene [56] through caged populations of Drosophila; results that immediately caught the attention of the vector biology community [43]. While the P element is not active outside of Drosophilids [57] and other DNA elements such as mariner/Mos 1 [58], Hermes [59], and piggyBac [60, 61] could not be efficiently remobilized in Ae. aegypti , highly efficient re-mobilization of piggyBac has been demonstrated in An.…”