Tomoyasu Sugiyama

TL;DR: The purification of an RNAi effector complex termed RITS (RNA-induced initiation of transcriptional gene silencing) that is required for heterochromatin assembly in fission yeast is described and a mechanism for the role of the RNAi machinery and small RNAs in targeting of heterochROMatin complexes and epigenetic genesilencing at specific chromosomal loci is suggested.

TL;DR: It is found that Clr4/Suv39h predominantly silenced repeat elements whose derived transcripts, transcribed mainly by RNA polymerase II, serve as a source for siRNAs and an important role for the RNAi machinery in maintaining genomic integrity is uncovered.

TL;DR: It is shown that RNA interference machinery operates in cis as a stable component of heterochromatic domains with RITS tethered to silenced loci by methylation of histone H3 at Lys9, and suggests that tethering promotes the processing of transcripts and generation of additional siRNAs forheterochromatin maintenance.

TL;DR: It is shown that Clr3, a fission yeast homolog of mammalian class II HDACs, acts in a distinct pathway parallel to RNAi-directed heterochromatin nucleation to recruit Clr4 and mediate H3K9 methylation at the silent mating-type region and centromeres and that it limits RNA polymerase II accessibility to naturally silenced repeats at heterochromaatin domains.

TL;DR: It is shown that a point mutation within the catalytic domain of Rdp1 abolished its RNA-dependent RNA polymerase activity and resulted in the loss of transcriptional silencing and heterochromatin at centromeres, together with defects in mitotic chromosome segregation and telomere clustering.