question: Are piRNAs involved in gene silencing?
answer: Piwi induces piRNA-guided transcriptional silencing and establishment of a repressive chromatin state. piRNA-guided slicing of transposon transcripts enforces their transcriptional silencing via specifying the nuclear piRNA repertoire. Transcriptional silencing implies a piRNA-mediated formation of repressive chromatin which diminishes the transcriptional capacity of the target locus.