Transcriptome-wide analyses of piRNA binding sites suggest distinct mechanisms regulate piRNA binding and silencing in C. elegans

A model depicting three distinct mechanisms that control piRNA binding and gene silencing on WAGO and CSR-1 targets. For WAGO targets (left), a CSR-1-independent mechanism promotes piRNAs binding at CDS (mechanism 1). WAGO 22G-RNA production, which is initiated by piRNA targeting, is therefore following a similar pattern of enrichment. For CSR-1 targets (right), CSR-1 blocks piRNA binding in a transcript-wide mode of action (mechanism 2). For downstream WAGO 22G-RNA production, CSR-1 acts locally to block WAGO 22G-RNA accumulation (mechanism 3).