Abstract
The germline genome serves as a crucial battleground for transposon expansion, as transposons can increase their copy numbers in offspring when activated within germ cells. Unexpectedly, during Drosophila spermatogenesis, the piRNA pathway, typically responsible for transposon silencing in female germ cells, is significantly downregulated, coinciding with a burst of transposon expression in spermatocytes. This suggests that germ cells might rely on alternative mechanisms for transposon suppression. By leveraging single-cell Smart-seq transcriptomic data, we found that transposon expression, Adar expression, and A-to-I RNA editing efficiency are markedly elevated in Drosophila spermatocytes. Adar mutant flies exhibit higher testicular TE expression, likely resulting from the loss of editing-mediated suppression. In the absence of a fully functional piRNA pathway in male germline, Adar-mediated RNA editing may act as an alternative mechanism for transposon silencing, highlighting a potential role for Adar in maintaining genome integrity.
