Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
Laboratório de Citogenética e Evolução Vegetal, Departamento de Botânica, Centro de Biociências, Universidade Federal de Pernambuco, Recife, PE, 50670-901, Brazil.
Nat Commun. 2024 Nov 5;15(1):9565. doi: 10.1038/s41467-024-53944-5.
In most studied eukaryotes, chromosomes are monocentric, with centromere activity confined to a single region. However, the rush family (Juncaceae) includes species with both monocentric (Juncus) and holocentric (Luzula) chromosomes, where centromere activity is distributed along the entire chromosome length. Here, we combine chromosome-scale genome assembly, epigenetic analysis, immuno-FISH and super-resolution microscopy to study the transition to holocentricity in Luzula sylvatica. We report repeat-based holocentromeres with an irregular distribution of features along the chromosomes. Luzula sylvatica holocentromeres are predominantly associated with two satellite DNA repeats (Lusy1 and Lusy2), while CENH3 also binds satellite-free gene-poor regions. Comparative repeat analysis suggests that Lusy1 plays a crucial role in centromere function across most Luzula species. Furthermore, synteny analysis between L. sylvatica (n = 6) and Juncus effusus (n = 21) suggests that holocentric chromosomes in Luzula could have arisen from chromosome fusions of ancestral monocentric chromosomes, accompanied by the expansion of CENH3-associated satellite repeats.
在大多数已研究的真核生物中，染色体是单中心的，着丝粒活性局限于单个区域。然而， rush 科（Juncaceae）包括具有单中心（Juncus）和全中心（Luzula）染色体的物种，其中着丝粒活性沿着整个染色体长度分布。在这里，我们结合染色体尺度的基因组组装、表观遗传分析、免疫荧光原位杂交和超分辨率显微镜来研究 Luzula sylvatica 向全中心性的转变。我们报告了基于重复的全中心体，其特征沿着染色体不规则分布。Luzula sylvatica 全中心体主要与两个卫星 DNA 重复序列（Lusy1 和 Lusy2）相关，而 CENH3 也结合无卫星的基因贫乏区域。比较重复分析表明，Lusy1 在大多数 Luzula 物种的着丝粒功能中起着至关重要的作用。此外，L. sylvatica（n=6）和 Juncus effusus（n=21）之间的同线性分析表明，Luzula 的全中心染色体可能是由祖先单中心染色体的染色体融合产生的，伴随着 CENH3 相关卫星重复序列的扩张。
