The arrangement of centromeres within the nucleus differs among species and cell types. However, neither the mechanisms determining centromere distribution nor its biological significance are currently well understood. In this study, we demonstrate the importance of centromere distribution for the maintenance of genome integrity through the cytogenic and molecular analysis of mutants defective in centromere distribution. We propose a two-step regulatory mechanism that shapes the non-Rabl-like centromere distribution in Arabidopsis thaliana through condensin II and the linker of the nucleoskeleton and cytoskeleton (LINC) complex. Condensin II is enriched at centromeres and, in cooperation with the LINC complex, induces the scattering of centromeres around the nuclear periphery during late anaphase/telophase. After entering interphase, the positions of the scattered centromeres are then stabilized by nuclear lamina proteins of the CROWDED NUCLEI (CRWN) family. We also found that, despite their strong impact on centromere distribution, condensin II and CRWN proteins have little effect on chromatin organization involved in the control of gene expression, indicating a robustness of chromatin organization regardless of the type of centromere distribution.

细胞核内着丝粒的排列因物种和细胞类型而异。然而，目前还不清楚决定着丝粒分布的机制及其生物学意义。在这项研究中，我们通过对着丝粒分布缺陷突变体的细胞遗传学和分子分析，证明了着丝粒分布对于维持基因组完整性的重要性。我们提出了一种两步调控机制，可塑造拟南芥中非 Rabl 样着丝粒分布通过凝聚素 II 和核骨架和细胞骨架 (LINC) 复合物的接头。Condensin II 在着丝粒处富集，并与 LINC 复合物合作，在后期后期/末期诱导着丝粒在核外围周围的散射。进入间期后，分散着丝粒的位置然后由 CROWDED NUCLEI (CRWN) 家族的核层蛋白稳定。我们还发现，尽管它们对着丝粒分布有很大影响，但凝聚素 II 和 CRWN 蛋白对参与基因表达控制的染色质组织几乎没有影响，这表明染色质组织的稳健性与着丝粒分布的类型无关。