Structural variation and DNA methylation shape the centromere-proximal meiotic crossover landscape in Arabidopsis
Structural variation and DNA methylation shape the centromere-proximal meiotic crossover landscape in Arabidopsis
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结构变异和DNA甲基化塑造了拟南芥着丝粒-近端减数分裂交叉景观
DOI：
10.1101/2023.06.12.544545
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Fernandes J
中科院分区：
文献类型：
--
作者：
Fernandes J
着丝粒将着丝粒复合物装载到染色体上，介导纺锤体附着并在细胞分裂过程中实现分离。虽然着丝粒执行保守的细胞功能，但其潜在的DNA序列在物种内部和物种之间高度不同。尽管DNA序列存在差异，但在真核生物中，着丝粒也普遍受到减数分裂交叉重组的抑制。然而，抑制着丝粒交叉的遗传和表观遗传因素仍未完全确定。结果为了探索着丝粒-近端减数分裂重组格局，我们绘制了14397个与完全组装的拟南芥（darabidopsis thaliana， A.）杂交的图谱。芥)genomes.A。塔利纳无丝粒包括装载含有CENH3组蛋白变体的核小体的大碱基卫星重复序列。每条染色体包含一个约3-4兆碱基的结构多态性区域，该区域缺乏交叉，包括卫星阵列。这个多态区域的两侧是1-2兆基的低重组区。这些重组抑制区域富含Gypsy/Ty3反转录转座子，另外还含有具有高遗传多样性的表达基因，这些基因可以启动减数分裂重组，但不会交叉。我们在cen3附近以高分辨率绘制交叉图，它解决了点状着丝粒-近端热点，这些热点重叠了嵌入在异染色质中的基因岛。着丝粒被密集的DNA甲基化，重组景观在DNA甲基化突变体中被重塑。我们观察到，在CG （met1）和非CG （cmt3）突变体中，着丝粒低重组区分别减少和增加交叉，而核心非重组区仍然受到抑制。结论本工作涉及a的遗传和表观遗传组织。在cenh3占据的卫星重复序列周围的交叉抑制区，将塔状无丝粒和侧翼的近中心点异染色质。
BackgroundCentromeres load kinetochore complexes onto chromosomes, which mediate spindle attachment and allow segregation during cell division. Although centromeres perform a conserved cellular function, their underlying DNA sequences are highly divergent within and between species. Despite variability in DNA sequence, centromeres are also universally suppressed for meiotic crossover recombination, across eukaryotes. However, the genetic and epigenetic factors responsible for suppression of centromeric crossovers remain to be completely defined.ResultsTo explore the centromere-proximal meiotic recombination landscape, we map 14,397 crossovers against fully assembledArabidopsis thaliana(A. thaliana) genomes.A. thalianacentromeres comprise megabase satellite repeat arrays that load nucleosomes containing the CENH3 histone variant. Each chromosome contains a structurally polymorphic region of ~3–4 megabases, which lack crossovers and include the satellite arrays. This polymorphic region is flanked by ~1–2 megabase low-recombination zones. These recombination-suppressed regions are enriched for Gypsy/Ty3 retrotransposons, and additionally contain expressed genes with high genetic diversity that initiate meiotic recombination, yet do not crossover. We map crossovers at high-resolution in proximity toCEN3, which resolves punctate centromere-proximal hotspots that overlap gene islands embedded in heterochromatin. Centromeres are densely DNA methylated and the recombination landscape is remodelled in DNA methylation mutants. We observe that the centromeric low-recombining zones decrease and increase crossovers in CG (met1) and non-CG (cmt3) mutants, respectively, whereas the core non-recombining zones remain suppressed.ConclusionOur work relates the genetic and epigenetic organization ofA. thalianacentromeres and flanking pericentromeric heterochromatin to the zones of crossover suppression that surround the CENH3-occupied satellite repeat arrays.
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DOI：
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发表时间：
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期刊：
bioRxiv
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