Probable ATP-binding RNA helicase required during spermatogenesis to repress transposable elements and preventing their mobilization, which is essential for the germline integrity. Acts via the piRNA metabolic process, which mediates the repression of transposable elements during meiosis by forming complexes composed of piRNAs and Piwi proteins and governs the methylation and subsequent repression of transposons. ATP + H2O = ADP + H(+) + phosphate Interacts (via Tudor domain 2) with Siwi (PubMed:24067652). Component of the PET complex, at least composed of EXD1, SIWI, TDRD12 and piRNAs (PubMed:26669262). At 36 hours after oviposition, detected in the nucleus and the cytosol where it is associated with chromosomes and to the surface of the nuclear membrane (PubMed:17098166). Component of the meiotic nuage, also named P granule, a germ-cell-specific organelle required to repress transposon activity during meiosis (PubMed:24067652). Expressed in the yolk cells. Not detected in yolk granules. Detected in non-diapause eggs through all stages of development. Detected only from 0-12 hours after oviposition in diapause eggs. Also expressed in diapause eggs following artificial diapause termination.