GSE125911
Abo1 is required for H3K9me2 to H3K9me3 transition in telomeric and centromeric heterochromatin [ChIP-seq]
Regulation of heterochromatin is critical for genome stability. Different states of methylated H3K9 have been discovered with distinct roles in heterochromatin formation and silencing. However, the control of the transition from H3K9me2 to H3K9me3 is still unclear. Here we investigate the role of the conserved bromodomain AAA-ATPase, Abo1, involved in maintaining the global nucleosome organization in fission yeast. We identified several key factors involved in heterochromatin silencing to interact genetically with Abo1: the histone deacetylase Clr3, the H3K9 methyltransferase Clr4, and the HP1 homologue  Swi6. Cells lacking Abo1 display an imbalance of H3K9me2 and H3K9me3 in heterochromatin. In abo1? cells, the centromeric constitutive heterochromatin had increased H3K9me2 but decreased H3K9me3 levels compared to wild type. In contrast, facultative heterochromatin regions, show both reduced H3K9me2 and H3K9me3 levels in abo1?. Genome-wide analysis showed that abo1? cells have silencing defects in both centromeres and subtelomeres, but not in a subset of heterochromatin islands. Our work uncovers a new role for Abo1 in supporting Clr4 activity and allowing for the transition of H3K9me2 to H3K9me3 in telomeric and centromeric heterochromatin. Overall design: Total 8 samples: 4 Input files with the corresponding 4 H3K9me2 ChIP samples in wild type and abo1? strain (two replicates)