小柯机器人

英国剑桥大学Ian R. Henderson等研究人员合作揭示拟南芥中心粒中卫星和转座子演化的循环。该研究于2023年5月17日在线发表于国际一流学术期刊《自然》。

研究人员表示，中心粒对细胞分裂至关重要，它装载CENH3或CENPA组蛋白变异核糖体，指导动粒的形成并使染色体分离。尽管它们的功能是保守的，但中心粒的大小和结构在不同的物种中是不同的。为了理解这种中心粒的悖论，有必要了解中心粒的多样性是如何产生的，以及它是否反映了古老的跨物种变异，还是反映了物种分化后的快速变化。

为了解决这些问题，研究人员收集了来自66个拟南芥和2个琴叶拟南芥的346个中心粒，这些中心粒显示了显著的种内和种间多样性。拟南芥的中心粒重复阵列被嵌入到连锁区块中，尽管内部的卫星在不断周转，这与单向基因转换或姐妹染色体之间的不平等交叉在序列多样化中的作用相一致。此外，亲着丝粒的ATHILA转座子最近侵入了卫星阵列。为了对付ATHILA的入侵，卫星同源化的染色体特异性爆发产生高阶重复并清除转座子，与重复演化的周期相一致。在拟南芥和琴叶拟南芥之间的比较中，中心粒的序列变化甚至更加极端。总之，这些研究结果确定了转座子通过卫星同质化入侵和清除的快速周期，它推动了中心粒的演化，并最终促成了物种演化。

附：英文原文

Title: Cycles of satellite and transposon evolution in Arabidopsis centromeres

Author: Wlodzimierz, Piotr, Rabanal, Fernando A., Burns, Robin, Naish, Matthew, Primetis, Elias, Scott, Alison, Mandkov, Terezie, Gorringe, Nicola, Tock, Andrew J., Holland, Daniel, Fritschi, Katrin, Habring, Anette, Lanz, Christa, Patel, Christie, Schlegel, Theresa, Collenberg, Maximilian, Mielke, Miriam, Nordborg, Magnus, Roux, Fabrice, Shirsekar, Gautam, Alonso-Blanco, Carlos, Lysak, Martin A., Novikova, Polina Y., Bousios, Alexandros, Weigel, Detlef, Henderson, Ian R.

Issue&Volume: 2023-05-17

Abstract: Centromeres are critical for cell division, loading CENH3 or CENPA histone variant nucleosomes, directing kinetochore formation and allowing chromosome segregation1,2. Despite their conserved function, centromere size and structure are diverse across species. To understand this centromere paradox3,4, it is necessary to know how centromeric diversity is generated and whether it reflects ancient trans-species variation or, instead, rapid post-speciation divergence. To address these questions, we assembled 346 centromeres from 66 Arabidopsis thaliana and 2 Arabidopsis lyrata accessions, which exhibited a remarkable degree of intra- and inter-species diversity. A.thaliana centromere repeat arrays are embedded in linkage blocks, despite ongoing internal satellite turnover, consistent with roles for unidirectional gene conversion or unequal crossover between sister chromatids in sequence diversification. Additionally, centrophilic ATHILA transposons have recently invaded the satellite arrays. To counter ATHILA invasion, chromosome-specific bursts of satellite homogenization generate higher-order repeats and purge transposons, in line with cycles of repeat evolution. Centromeric sequence changes are even more extreme in comparison between A.thaliana and A.lyrata. Together, our findings identify rapid cycles of transposon invasion and purging through satellite homogenization, which drive centromere evolution and ultimately contribute to speciation.

DOI: 10.1038/s41586-023-06062-z

Source: https://www.nature.com/articles/s41586-023-06062-z

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
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