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Bobkov, Georg O. M.; Huang, Anming; Berg, Sebastiaan J. W. van den; Mitra, Sreyoshi; Anselm, Eduard; Lazou, Vasiliki; Schunter, Sarah; Feederle, Regina; Imhof, Axel; Lusser, Alexandra; Jansen, Lars E. T. und Heun, Patrick (2020): Spt6 is a maintenance factor for centromeric CENP-A. In: Nature Communications, Bd. 11, Nr. 1, 2919 [PDF, 4MB]

Abstract

Replication and transcription of genomic DNA requires partial disassembly of nucleosomes to allow progression of polymerases. This presents both an opportunity to remodel the underlying chromatin and a danger of losing epigenetic information. Centromeric transcription is required for stable incorporation of the centromere-specific histone dCENP-A in M/G1 phase, which depends on the eviction of previously deposited H3/H3.3-placeholder nucleosomes. Here we demonstrate that the histone chaperone and transcription elongation factor Spt6 spatially and temporarily coincides with centromeric transcription and prevents the loss of old CENP-A nucleosomes in both Drosophila and human cells. Spt6 binds directly to dCENP-A and dCENP-A mutants carrying phosphomimetic residues alleviate this association. Retention of phosphomimetic dCENP-A mutants is reduced relative to wildtype, while non-phosphorylatable dCENP-A retention is increased and accumulates at the centromere. We conclude that Spt6 acts as a conserved CENP-A maintenance factor that ensures long-term stability of epigenetic centromere identity during transcription-mediated chromatin remodeling.

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