Reference - PMID:32499408 - The molecular chaperone Hsp90 regulates heterochromatin assembly through stabilizing multiple complexes in fission yeast.
Reference summary
- PubMed ID
- PMID:32499408
- Title
- The molecular chaperone Hsp90 regulates heterochromatin assembly through stabilizing multiple complexes in fission yeast.
- Authors
- Sun L, Liu XM, Li WZ, Yi YY, He X, Wang Y, Jin QW
- Citation
- J Cell Sci 2020 Jul 07;133(13)
- Publication year
- 2020
- Abstract
- In the fission yeast Schizosaccharomyces pombe , both RNAi machinery and RNAi-independent factors mediate transcriptional and posttranscriptional silencing and heterochromatin formation. Here, we show that the silencing of reporter genes at major native heterochromatic loci (centromeres, telomeres, mating-type locus and rDNA regions) and an artificially induced heterochromatin locus is alleviated in a fission yeast hsp90 mutant, hsp90-G84C Also, H3K9me2 enrichment at heterochromatin regions, especially at the mating-type locus and subtelomeres, is compromised, suggesting heterochromatin assembly defects. We further discovered that Hsp90 is required for stabilization or assembly of the RNA-induced transcriptional silencing (RITS) and Argonaute siRNA chaperone (ARC) RNAi effector complexes, the RNAi-independent factor Fft3, the shelterin complex subunit Poz1 and the Snf2/HDAC-containing repressor complex (SHREC). Our ChIP data suggest that Hsp90 regulates the efficient recruitment of the methyltransferase/ubiquitin ligase complex CLRC by shelterin to chromosome ends and targeting of the SHREC and Fft3 to mating type locus and/or rDNA region. Finally, our genetic analyses demonstrated that increased heterochromatin spreading restores silencing at subtelomeres in the hsp90-G84C mutant. Thus, this work uncovers a conserved factor critical for promoting RNAi-dependent and -independent heterochromatin assembly and gene silencing through stabilizing multiple effectors and effector complexes.
