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Centromeres play essential roles in the proper segregation of chromosomes by directing the assembly of the kinetochore complex. How centromere identity is established and maintained remains a fundamental question in biology. In most eukaryotes, centromere is defined epigenetically by Centromere Protein- A (CENP-A), a centromere-specific histone 3 (H3) variant. |
The amount of CENP-A at centromeres is tightly regulated. But how the proper level of CENP-A is maintained at centromeres is still unknown. Also, how ectopic CENP-A chromatin is prevented from assembling at non-centromeric regions remains poorly understood. Through a visual genetic screen, Li group identified a conserved but uncharacterized protein, Ccp1, as a factor capable of antagonizing the loading of CENP-A at both centromeric and non-centromeric regions.
This study provides mechanistic insight into how CENP-A homeostasis is maintained at centromeres, and also uncovers a critical missing link for how the cells protects themselves from erroneously assembling CENP-A at ectopic regions. This works was recently published in Molecular Cell titled “Ccp1 Homodimer Mediates Chromatin Integrity by Antagonizing CENP-A Loading”. The paper can be accessed here.