Functions of piRNAs and the Piwi protein in Drosophila

Short (25-35 nucleotides) regulatory piPHK, along with RNA-binding proteins of the Piwi family, constitute an evolutionarily conserved system that functions mainly in eukaryotic gonads. The system can be regarded as a variant of the mechanism of RNA interference, which is based on the recognition of target RNA as a result of complementary interactions with piRNA. The variants of this regulatory system function in the germline cells, including stem cells and somatic cells of the niche, ensuring maintenance of the germline stem cells and their differentiation. One of the most important functions (but not the only one) of this system is the repression of transposons, which guarantees genome stability in germline cells. This review focuses on the works of the authors of the review in the context of outstanding international achievements in a rapidly evolving re- search area, the biology of piRNA and the function of the Piwi protein.