An Hsp70 Chaperone Is Involved in Meiotic Silencing by Unpaired DNA

In the filamentous fungus <i>Neurospora crassa</i>, a gene not having a pairing partner during meiosis is seen as a potential intruder and is targeted by a mechanism called meiotic silencing by unpaired DNA (MSUD). MSUD employs core RNA interference (RNAi) components such as the SMS-2 Argonaute, which uses small interfering RNAs (siRNAs) as guides to seek out mRNAs from unpaired genes for silencing. In <i>Drosophila melanogaster</i>, the heat shock protein 70 (Hsp70) chaperone system facilitates the conformational activation of an Argonaute and allows it to load siRNAs. Here, our results demonstrate that an Hsp70 protein in <i>Neurospora</i> interacts with SMS-2 and mediates the silencing of unpaired genes.