Trimethylguanosine synthase 1 (Tgs1) is involved in Swi6/HP1‐independent siRNA production and establishment of heterochromatin in fission yeast

In fission yeast, siRNA generated by RNA interference (RNAi) factors plays critical roles in establishment and maintenance of heterochromatin. To achieve efficient synthesis, RNAi assemble on heterochromatin via association with Swi6, a homologue protein 1 (HP1), heterochromatic noncoding (hncRNA) retained chromatin. addition, spliceosomes formed hncRNA introns recruit to Small nuclear RNAs, components the spliceosome, have trimethylguanosine (TMG) cap that is Tgs1-dependent hypermethylation normal m7G cap; this required for splicing some mRNAs budding yeast Drosophila. study, we found loss Tgs1 destabilizes centromeric was Swi6-independent as well Loss affected efficiency absence Swi6. Furthermore, hncRNAs TMG cap, diminished chromatin binding these hncRNAs. Together, results suggest ensuring spliceosome-dependent recruitment regulating between hncRNA.