Lev, Itamar et al. (2017) International Worm Meeting "Untangling the Role of H3K9 Methylations in Transgenerational Small RNA Inheritance."

Seroussi, Uri, Bril, Roberta, Anava, Sarit, Rechavi, Oded, Gingold, Hila, Lev, Itamar

[International Worm Meeting, 2017]

In recent years transgenerational inheritance of acquired traits has been described in various species. Both small interfering RNAs (siRNAs) and chromatin modifications have been implicated in the maintenance of such heritable responses. In plants and yeast, a self-reinforcing feedforward loop was described, where nuclear siRNAs direct histone methylation at pericentromeric regions and in return, the siRNA machinery is recruited to pericentromeric methylated histones to synthesize additional siRNAs. In Caenorhabditis elegans, double-stranded RNA-induced RNA interference (RNAi) can produce long-term heritable silencing responses that involve the production of "secondary" siRNAs and histone methylation of the targeted locus. Recently, we showed that MET-2, a histone-H3 Lysine-9 mono/di- methyltransferase, suppresses transgenerational RNAi inheritance indirectly by affecting small RNA biogenesis. The current work discusses how chromatin modifications affect small RNA biogenesis and the different requirements for heritable silencing of transgenes and endogenous genes.