Coordination of meiotic recombination and prophase I progression in plants: the role of retinoblastoma (RBR)

植物减数分裂重组和前期 I 进展的协调：视网膜母细胞瘤 (RBR) 的作用

• 批准号: BB/K007505/1
• 负责人: Chris Franklin
• 金额: $ 60.74万
• 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: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FK007505%2F1
• 关键词: Coordination; meiotic; recombination; prophase; progression

It is predicted that as a result of population increase, industrialization and climate change global demand for food will double by 2050 (Reaping the Benefit: Royal Society Review 2009). To meet this challenge it will be necessary to develop new crop varieties that are improved in various ways, for example, increased nutritional value and yield and tolerance to biotic and abiotic stresses. Although GM has its part to play, the development of new varieties will remain highly dependent on methodologies derived from traditional breeding methods which are reliant on meiotic recombination to generate variation through the formation of genetic crossovers (COs) which results in new combinations of genes. Understanding the factors that control meiotic recombination is of great significance for the improvement of crop-breeding since it is now clear that many species notably cereals, possess large regions on their chromosomes that rarely recombine. This presents a significant barrier for the introgression of new genetic traits. Hence, to overcome this problem we need to know how the frequency and distribution of COs are controlled. In addition an estimated 50% of plants are polyploid, which creates an additional level of meiotic regulation that we need to understand. Studies indicate that the controlled formation of COs is dependent on the interplay between the proteins that catalyse recombination and those that regulate the extensive remodelling of chromosomes during prophase I of meiosis. How these processes are coordinated remains poorly understood. Recently, we obtained the first evidence in any organism, that the retinoblastoma protein Rb (RBR in plants) plays an essential role in the control of meiotic recombination. The function of Rb in mitotic cell-cycle control and as a tumour-suppressor has been extensively studied. However, it is generally difficult to study its role in development in adult organisms as loss of Rb results in lethality during embryogenesis. Using a specific rbr mutant we have been able to overcome this problem. Our studies reveal an important coordinating role for RBR in meiosis through a direct interaction with the meiotic chromosomes at the sites of recombination. We now propose to investigate how RBR exerts this coordinating role. In particular we aim to establish how RBR links with components of the cell-cycle machinery to ensure that chromosome remodelling occurs in a timely fashion in relation to meiotic recombination and investigate if it functions as "sensor" to link meiosis with changes in temperature. Although studies will primarily be conducted in the model plant Arabidopsis, as this is the most experimentally tractable system, these will be complimented by additional work in crop species. Our experimental strategy will be based around molecular cytogenetics using antibodies that recognize key meiotic proteins combined with high resolution light microscopy to study meiotic prophase I in wild-type plants and a range of meiotic mutants, including a line lacking RBR. Interactions between RBR, meiotic proteins and cell-cycle components will be studied using mass-spectrometry to analysis protein complexes that have been precipitated from meiocytes using an anti-RBR antibody. Yeast two-hybrid analysis will be used as an alternative strategy and to confirm putative interactions. A further aspect of the analysis will be to investigate the role of RBR in coordinating chromosome pairing and recombination in polyploid organisms. Specifically, we will investigate the relationship between RBR and the function of the Ph1 locus in wheat which is important for the control of chromosome pairing in this hexaploid species. We anticipate these studies will provide important new insights into the control of recombination during meiosis that will be of benefit for plant breeding by providing approaches to enable changes in CO frequency and distribution.

据预测，由于人口增长、工业化和气候变化，到2050年，全球对粮食的需求将翻一番（《收获利益：皇家学会评论2009》）。为了应对这一挑战，有必要开发新的作物品种，以各种方式进行改良，例如提高营养价值和产量，以及对生物和非生物胁迫的耐受性。虽然转基因有它的作用，但新品种的开发仍将高度依赖于传统育种方法的方法，这些方法依赖于减数分裂重组，通过形成遗传杂交（COs）来产生变异，从而产生新的基因组合。了解控制减数分裂重组的因素对改进作物育种具有重要意义，因为现在很清楚，许多物种，特别是谷物，在其染色体上具有很少重组的大区域。这对新遗传性状的渗入构成了重大障碍。因此，为了克服这个问题，我们需要知道如何控制COs的频率和分布。此外，估计有50%的植物是多倍体，这就产生了一个我们需要了解的额外的减数分裂调节水平。研究表明，COs的受控形成依赖于催化重组的蛋白质和减数分裂前期染色体广泛重塑的蛋白质之间的相互作用。这些过程如何协调仍然知之甚少。最近，我们首次在生物体中获得证据，证明视网膜母细胞瘤蛋白Rb（植物中的RBR）在控制减数分裂重组中起重要作用。Rb在有丝分裂细胞周期调控和肿瘤抑制中的作用已被广泛研究。然而，通常很难研究它在成年生物发育中的作用，因为Rb的缺失会导致胚胎发生期间的死亡。使用一种特殊的rbr突变体，我们已经能够克服这个问题。我们的研究揭示了RBR通过与减数分裂染色体在重组位点的直接相互作用，在减数分裂中起着重要的协调作用。我们现在建议研究RBR如何发挥这种协调作用。特别是，我们的目标是建立RBR如何与细胞周期机制的组成部分联系起来，以确保染色体重塑在减数分裂重组中及时发生，并研究它是否作为“传感器”将减数分裂与温度变化联系起来。虽然研究将主要在模式植物拟南芥中进行，因为这是实验上最容易处理的系统，但这些研究将在作物物种中进行额外的工作。我们的实验策略将基于分子细胞遗传学，使用识别关键减数分裂蛋白的抗体结合高分辨率光学显微镜研究野生型植物和一系列减数分裂突变体的减数分裂前期I，包括缺乏RBR的系。RBR、减数分裂蛋白和细胞周期组分之间的相互作用将使用质谱法研究，以分析使用抗RBR抗体从减数细胞中沉淀的蛋白质复合物。酵母双杂交分析将用作替代策略，并确认假定的相互作用。分析的另一个方面将是研究RBR在多倍体生物中协调染色体配对和重组中的作用。具体来说，我们将研究RBR与Ph1位点的功能之间的关系，Ph1位点在小麦这个六倍体物种中对染色体配对的控制很重要。我们预计这些研究将为减数分裂期间的重组控制提供重要的新见解，通过提供使CO频率和分布发生变化的方法，这将有利于植物育种。

项目成果

Arabidopsis PCH2 Mediates Meiotic Chromosome Remodeling and Maturation of Crossovers

拟南芥 PCH2 介导减数分裂染色体重塑和交叉成熟

• DOI: 10.17615/pp5r-xg77
• 发表时间: 2015
• 作者: Armstrong, Susan J.

The challenge of evolving stable polyploidy: could an increase in "crossover interference distance" play a central role?

• DOI: 10.1007/s00412-015-0571-4
• 发表时间: 2016-06
• 期刊: Chromosoma
• 影响因子: 1.6
• 作者: Bomblies K;Jones G;Franklin C;Zickler D;Kleckner N
• 通讯作者: Kleckner N

Atypical centromeres in plants-what they can tell us.

• DOI: 10.3389/fpls.2015.00913
• 发表时间: 2015
• 期刊: Frontiers in plant science
• 影响因子: 5.6
• 作者: Cuacos M;H Franklin FC;Heckmann S
• 通讯作者: Heckmann S

Arabidopsis PCH2 Mediates Meiotic Chromosome Remodeling and Maturation of Crossovers.

• DOI: 10.1371/journal.pgen.1005372
• 发表时间: 2015-07
• 期刊: PLoS genetics
• 影响因子: 4.5
• 作者: Lambing C;Osman K;Nuntasoontorn K;West A;Higgins JD;Copenhaver GP;Yang J;Armstrong SJ;Mechtler K;Roitinger E;Franklin FC
• 通讯作者: Franklin FC

Arabidopsis meiotic crossover hot spots overlap with H2A.Z nucleosomes at gene promoters.

• DOI: 10.1038/ng.2766
• 发表时间: 2013-11
• 期刊: NATURE GENETICS
• 影响因子: 30.8
• 作者: Choi, Kyuha;Zhao, Xiaohui;Kelly, Krystyna A.;Venn, Oliver;Higgins, James D.;Yelina, Nataliya E.;Hardcastle, Thomas J.;Ziolkowski, Piotr A.;Copenhaver, Gregory P.;Franklin, F. Chris H.;McVean, Gil;Henderson, Ian R.
• 通讯作者: Henderson, Ian R.