An unstructured MET-2/SETDB1 cofactor ensures H3K9me2, focus formation and perinuclear anchoring [RNA-seq]
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ABSTRACT: The segregation of the genome into accessible euchromatin and histone H3 lysine 9 methylated (H3K9me) heterochromatin is essential for the repression of repetitive elements and tissue-specific genes. In C. elegans, the SETDB1 homolog MET-2 catalyzes H3K9me1 and me2. In worms as in vertebrates, the regulation of this crucial enzyme remains enigmatic. Contrary to the localization of overexpressed MET-2, we find endogenous MET-2 to be nuclear throughout development, enriched in perinuclear foci in a cell cycle-dependent manner. We show by mass spectrometry that MET-2 associates with a highly unstructured protein, LIN-65, and a conserved GTPase effector ARLE-14. All three colocalize at heterochromatic foci. Ablation of lin-65, but not arle-14, mislocalizes and destabilizes MET-2, resulting in decreased H3K9me2, derepression of MET-2 targets, and loss of fertility. Importantly, mutation of met-2 or lin-65 is sufficient to disrupt the perinuclear clustering of heterochromatin genome-wide. Thus, LIN-65 is an essential cofactor of MET-2 required for H3K9me2 deposition, heterochromatin clustering, perinuclear anchoring, and transcriptional repression.
ORGANISM(S): Caenorhabditis elegans
PROVIDER: GSE122339 | GEO | 2019/02/06
REPOSITORIES: GEO
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