Faithful chromosome segregation during cell division relies on the centromere, a unique chromosomal locus that ensures proper kinetochore assembly and microtubule attachment. Unlike most chromosomal regions, the centromere is not defined by a specific DNA sequence but by the presence of the histone H3 variant CENP-A, which replaces canonical H3 within centromeric nucleosomes1,2,3,4,5,6. The incorporation of CENP-A is both necessary and sufficient for centromere function, and its propagation across cell generations underlies the epigenetic inheritance of the centromere position2,7,8,9. Despite substantial progress in understanding the CENP-A nucleosome structure and centromere identity maintenance, the specific structural features underlying this process remain incompletely defined. A long-standing controversy has surrounded the structural nature of the CENP-A nucleosome—whether it adopts a canonical octameric configuration similar to histone H3 nucleosomes or instead forms a noncanonical nucleosome such as a hemisome, composed of single subunits of H2A, H2B, CENP-A, and H410,11,12,13,14,15. Early biochemical and biophysical studies suggested that the CENP-A nucleosome might exhibit noncanonical, tetrameric arrangements, raising the possibility that hemisomes could represent a centromere-specific nucleosome form10,13,16. Subsequent reports proposed that CENP-A nucleosomes might exist as tetramers rather than octamers in certain cell-cycle states17,18, whereas other studies argued that the native form adopts the canonical octameric...

Centromeres are critical for accurate segregation of chromosomes and are often composed of megabases of tandemly arranged satellite repeats. Yet, despite their conserved function, the DNA sequence of ...

Centromeres are critical for accurate segregation of chromosomes and are often composed of megabases of tandemly arranged satellite repeats. Yet, despite their conserved function, the DNA sequence of ...

The large, repeat-rich, and highly heterozygous rye (Secale cereale L.) genome has posed significant challenges for genome assembly. Here, the authors present an improved rye genome assembly and uncov...

Researchers in the Basic Sciences Division track evolutionary origins for an essential protein

Yang et al. show that α-satellite RNA, derived from human centromeric satellite repeats, forms R-loops at human centromeres to ensure faithful chromosome segregation by recruiting Shugoshin 1. This mechanism is essential for preserving chromosomal stability.

We present two near-complete triticale genome assemblies and perform pan-centromere analyses across >200 haplotypes from parental species, synthetic allopolyploids, cultivars, and 337 resequenced acc...

Read the full paper: Haplotype-resolved DiMeLo-seq maps centromeric chromatin in a complete diploid human genome

To generate a high-quality reference assembly for rye Lo7, we employed the TRITEX pipeline33, integrating data generated by multiple advanced sequencing technologies: PacBio HiFi reads (38-fold haploid coverage), ONT long reads (>25 kb, ninefold coverage), and Hi-C reads (20-fold coverage) for chromosome-level scaffolding (Supplementary Fig. 1a, and Supplementary Table 1). We estimated the heterozygosity of Lo7 using k-mer analysis, determining it to be 0.06% (Supplementary Fig. 1b). We performed flow cytometric genome size measurements using a recalculated estimate for the reference standard5, which resulted in a revised value of approximately 7 Gb for Lo7, indicating that the absolute genome size is smaller than that of previously assumed34 (Supplementary Table 2). The initial contigs were assembled by combining HiFi and ONT long reads using hifiasm35. These contigs were manually curated with Hi-C data to generate a draft assembly (Supplementary Fig. 2), which was further evaluated and refined using an optical genome map (Supplementary Fig. 3, and Supplementary Table 3). Finally, genome annotation was conducted using RNA-seq and Iso-seq data (Fig. 1). Additional features were systematically annotated, including chromosome lengths, repetitive sequences, centromere locations, and 5mCpG methylation (Fig. 1). The final assembly spanned 6.76 Gb, with a contig N50 of 128 Mb...

Yang et al. show that α-satellite RNA, derived from human centromeric satellite repeats, forms R-loops at human centromeres to ensure faithful chromosome segregation by recruiting Shugoshin 1. This me...