The centromere is a vital locus on each chromosome which seeds the kinetochore, allowing for a physical connection between the chromosome and the mitotic spindle. At the heart of the centromere is the centromere-specific histone H3 variant CENP-A/CENH3. Throughout the cell cycle the constitutive centromere associated network is bound to CENP-A chromatin, but how this protein network modifies CENP-A nucleosome dynamics in vivo is unknown. Here, using a combination of biophysical and biochemical analyses we provide evidence for the existence of two populations of structurally distinct CENP-A nucleosomes that co-exist at human centromeres. These two populations display unique sedimentation patterns,…
Long-read sequencing, CENP-A ChIP, and chromatin fiber imaging reveal the composition and organization of Drosophila melanogaster centromeres, which have long remained elusive despite the high quality of this species’ genome. assembly.
Despite the conserved essential function of centromeres, centromeric DNA itself is not conserved. The histone-H3 variant, CENP-A, is the epigenetic mark that specifies centromere identity. Paradoxically, CENP-A normally assembles on particular sequences at specific genomic locations. To gain insight into the specification of complex centromeres, here we take an evolutionary approach, fully assembling genomes and centromeres of related fission yeasts. Centromere domain organization, but not sequence, is conserved between Schizosaccharomyces pombe, S. octosporus and S. cryophilus with a central CENP-ACnp1 domain flanked by heterochromatic outer-repeat regions. Conserved syntenic clusters of tRNA genes and 5S rRNA genes occur across the centromeres…