Integration of chromosome synapsis and recombination by AtZYP1 during Arabidopsis meiosis

拟南芥减数分裂过程中AtZYP1对染色体突触的整合和重组

• 批准号: BB/E006469/1
• 负责人: Chris Franklin
• 金额: $ 49.7万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE006469%2F1
• 关键词: Integration; chromosome; synapsis; recombination; AtZYP1

Meiosis occupies a central role in the life cycles of all sexually reproducing eukaryotes. An understanding of this process is critical to furthering research on reproduction, fertility, genetics and breeding. Meiosis is a specialized form of cell-division during which a single round of DNA replication is followed by two cell-divisions thereby reducing the chromosome content from diploid to haploid. Accurate segregation of homologous chromosomes at the first meiotic division is dependent on the formation of physical connections, known as chiasmata, between homologous chromosome pairs (homologues). Chiasmata arise from homologous recombination during prophase I of meiosis and are the physical manifestation of genetic crossovers. In their absence the homologues segregate at random leading to the formation of aneuploid gametes following the separation of the sister chromatids at the second meiotic division. In the past few years it has emerged that the key events of meiosis, chromosome pairing and synapsis and homologous recombination that occur during prophase I of meiosis are highly integrated. Also, it is increasingly clear that many of the key decisions in the control of meiotic recombination occur in early prophase I at the time of the transition from leptotene to zygotene when homologous chromosome synapsis is initiated. Synapsis is mediated by the synaptonemal complex (SC), a structurally conserved, tripartite proteinaceous complex. The SC was discovered in 1956 and has subsequently been found in the majority of eukaryotes. It is comprised of two lateral elements running in parallel the length of the homologous chromosome pairs. These are separated by a distance of 100nm and are linked by transverse filaments that interdigitate to span the central region in a 'zipper-like' arrangement. Remarkably, the function of the SC remains a mystery. However, recent studies in budding yeast and our own in Arabidopsis point to a strong link between initiation of chromosome synapsis and the control of the recombination pathway. In this proposal it is our objective to elucidate the nature of this relationship in Arabidopsis. We have recently isolated ZYP1 the first SC protein to be identified in higher plants. It encodes the transverse filament of the SC. We have discovered that in the absence of ZYP1 normal recombination is perturbed such that inappropriate recombination events occur between non-homologous chromosomes. Hence accurate chromosome segregation at the first meiotic division is impossible. In this project we aim to establish how the ZYP1 protein prevents non-homologous recombination. Does it directly interact with the early recombination machinery to ensure the fidelity of recombination interactions? Or perhaps it affects chromosome dynamics in early prophase I, since is increasingly clear that there is a close relationship between the recombination pathway and chromosome organization throughout meiosis. We anticipate that these studies will establish for the first time a SC function beyond a simple structural role and provide further evidence that the biochemical processes that drive recombination are closely co-ordinated by chromosome dynamics

减数分裂在所有有性繁殖真核生物的生命周期中占有核心地位。对这一过程的理解对于进一步研究生殖、生育、遗传和繁殖至关重要。减数分裂是一种特殊的细胞分裂形式，在此过程中，一轮DNA复制之后是两次细胞分裂，从而使染色体含量从二倍体减少到单倍体。同源染色体在第一次减数分裂时的准确分离取决于同源染色体对(同源)之间物理连接的形成，即所谓的交叉。交叉是减数分裂前期I期同源重组的产物，是遗传交叉的物理表现。在没有它们的情况下，同系物随机分离，导致在第二次减数分裂时姐妹染色单体分离后形成非整倍体配子。在过去的几年里，发生在减数分裂前期I的减数分裂、染色体配对、联会和同源重组等关键事件高度整合。此外，越来越清楚的是，控制减数分裂重组的许多关键决定发生在早期前期I，当时同源染色体联会开始从细线型向合线型转变。突触是由联会复合体(SC)介导的，联会复合体是一种结构保守的三部分蛋白质复合体。SC于1956年被发现，随后在大多数真核生物中发现。它由两个与同源染色体对的长度平行的侧向元件组成。它们之间的距离为100 nm，并由横向细丝连接，横向细丝交错排列，以拉链形式横跨中央区域。值得注意的是，SC的功能仍然是一个谜。然而，最近对发芽酵母和我们自己在拟南芥中的研究表明，染色体突触的启动和重组途径的控制之间存在着强烈的联系。在这项建议中，我们的目标是阐明拟南芥中这种关系的性质。我们最近分离到了ZYP1，这是第一个在高等植物中发现的SC蛋白。它编码SC的横丝。我们发现，在没有ZYP1的情况下，正常的重组会受到干扰，以至于在非同源染色体之间会发生不适当的重组事件。因此，在第一次减数分裂时准确分离染色体是不可能的。在这个项目中，我们的目标是建立ZYP1蛋白如何防止非同源重组。它是否直接与早期重组机制相互作用，以确保重组相互作用的保真度？也可能是它影响了前期I期的染色体动力学，因为在整个减数分裂过程中，重组途径和染色体组织之间存在着密切的关系。我们预计，这些研究将首次确立SC的功能，超越简单的结构作用，并提供进一步的证据，证明推动重组的生化过程与染色体动力学密切协调

项目成果

Inter-homolog crossing-over and synapsis in Arabidopsis meiosis are dependent on the chromosome axis protein AtASY3.

拟南芥减数分裂中的血间交叉和突触取决于染色体轴蛋白ATASY3。

• DOI: 10.1371/journal.pgen.1002507
• 发表时间: 2012-02
• 期刊: PLoS genetics
• 影响因子: 4.5
• 作者: Ferdous M;Higgins JD;Osman K;Lambing C;Roitinger E;Mechtler K;Armstrong SJ;Perry R;Pradillo M;Cuñado N;Franklin FC
• 通讯作者: Franklin FC