The preRC protein ORCA organizes heterochromatin by assembling histone H3 lysine 9 methyltransferases on chromatin

• DOI: 10.7554/elife.06496
• Publication Date: 2015-04-28T11:39:35Z
• Authors: Sumanprava Giri; Vasudha Aggarwal; Julien Pontis; Zhen Shen; Arindam Chakraborty; Abid Khan; Craig Mizzen; Kannanganattu V P...; Slimane Ait-Si-Ali; Taekjip Ha; Supriya G Prasanth
• Keywords: Heterochromatin protein 1; Histone Methylation; Non-histone protein; PRC2; Histone code

Heterochromatic domains are enriched with repressive histone marks, including H3 lysine 9 methylation, written by methyltransferases (KMTs). The pre-replication complex protein, origin recognition complex-associated (ORCA/LRWD1), preferentially localizes to heterochromatic regions in post-replicated cells. Its role heterochromatin organization remained elusive. ORCA recognizes methylated H3K9 marks and interacts KMTs, G9a/GLP Suv39H1 a chromatin context-dependent manner. Single-molecule pull-down assays demonstrate that ORCA-ORC (Origin Recognition Complex) multiple KMTs exist single stabilizes KMT complex. Cells lacking show alterations architecture, significantly reduced di- tri-methylation at specific sites. Changes structure due loss of affect replication timing, the late-replicating regions. We acts as scaffold for establishment its association activity sites is crucial structure.