Shutdown rules in germline transposon silencing and piRNA production
In animal gonads, the piRNAs, bound to PIWI-clade Argonaute proteins, silence transposons and maintain genomic integrity. Failure of this pathway triggers transposon activation and induces DNA damage, resulting in sterility. Now, the Hannon, Pillai, and Brennecke labs* describe a new gene in the piRNA pathway, shutdown, which encodes an evolutionarily conserved FKBP-family co-chaperone protein. shutdown was originally discovered in a large-scale Drosophila genetic screen for female sterility (Schupbach and Wieschaus, 1991). Working in flies, the Hannon and Brennecke labs report that mutation of shutdown in fruit fly, like other piRNA pathway genes, leads to transposon de-silencing in both the somatic and germline cells of the ovary. Small RNA sequencing reveals that shutdown mutants block piRNA production. The C-terminal TPR …
