Watanabe Reito, Perea-Resa Carlos, Blower Michael D
bioRxiv. 2025 May 1:2025.04.29.651290. doi: 10.1101/2025.04.29.651290.
Centromeres are essential chromosomal components that ensure proper cell division by serving as assembly sites for kinetochores, which connect chromosomes to spindle microtubules. Centromeres are marked by the evolutionarily conserved centromere-specific histone H3 variant, CENP-A, which is deposited into centromere nucleosomes during G1 in human cells. Centromeres retain cohesin, a ring-like protein complex during mitosis, protecting sister chromatid cohesion and centromere transcription to prevent chromosome missegregation. Previous work in has suggested that centromere transcription and centromeric RNAs are important for CENP-A deposition in chromatin. During mitosis centromeric cohesin is critical for centromere transcription. However, it is not clear how or if centromeric transcription and cohesin contribute to CENP-A deposition in G1 in human cells. To address these questions, we combined a cell synchronization strategy with the Auxin Inducible Degron technology and transcription inhibition in human cells. In contrast to , our results demonstrated that neither centromeric transcription nor cohesin is required for CENP-A deposition in human cells. Our data demonstrate clear differences in the CENP-A deposition mechanism between human and cells. These findings provide deeper insights into the plasticity underlying centromere maintenance and highlight evolutionary divergence in centromere maintenance systems across species.
着丝粒是染色体的重要组成部分，它通过作为动粒的装配位点来确保细胞的正常分裂，而动粒将染色体与纺锤体微管相连。着丝粒由进化上保守的着丝粒特异性组蛋白H3变体CENP-A标记，在人类细胞的G1期，CENP-A被沉积到着丝粒核小体中。着丝粒在有丝分裂期间保留黏连蛋白，这是一种环状蛋白复合物，可保护姐妹染色单体的黏连和着丝粒转录，以防止染色体错误分离。之前的研究表明，着丝粒转录和着丝粒RNA对于CENP-A在染色质中的沉积很重要。在有丝分裂期间，着丝粒黏连蛋白对着丝粒转录至关重要。然而，尚不清楚着丝粒转录和黏连蛋白如何或是否有助于人类细胞G1期的CENP-A沉积。为了解决这些问题，我们将细胞同步策略与生长素诱导降解技术以及人类细胞中的转录抑制相结合。与之前研究不同的是，我们的结果表明，人类细胞中CENP-A的沉积既不需要着丝粒转录也不需要黏连蛋白。我们的数据表明人类细胞和其他细胞在CENP-A沉积机制上存在明显差异。这些发现为着丝粒维持的可塑性提供了更深入的见解，并突出了物种间着丝粒维持系统的进化差异。
