RNAi mediates allele-specific epigenetic inheritance of heterochromatin [ChIP-seq]

We tested the ability of trans siRNAs to establish a silent allele of endogenous ade6+ or an ade6+ transgene inserted within euchromatic loci. We found that a silent ade6-OFF epi-allele that grows red on low adenine medium could be established in several mutant backgrounds (mlo3∆, leo1∆) in the presence of ectopic siRNAs. Furthermore, we found that the silent ade6-OFF epi-allele could be meiotically inherited to wildtype progeny lacking the establishing mutation or ectopic siRNAs. Here, we sequenced genome-wide DNA associated with conserved heterochromatin markers and found that silencing of the endogenous ade6 locus correlates with increased spreading of H3K9me2 and H3K9me3. Additionally, heterochromatin domains established with cen::ade6 as the ectopic siRNA-producing locus were associated with significantly more spreading of H3K9me2 and H3K9me3 than those established using an ade6 hairpin as the driver siRNA-producing locus. Examination of H3K9me2 or H3K9me3