Cell Biological mechanisms of centromere drive

着丝粒驱动的细胞生物学机制

• 批准号: 10404859
• 负责人: Michael Lampson
• 金额: $ 42.66万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10404859
• 关键词: Address; Biological; Biological Models; Cell division; Cells; Centromere; Chemicals; Chromosome Segregation; Chromosomes; Conflict (Psychology); DNA; DNA Sequence; Defect; Development; Ensure; Evolution; Female; Genetic; Genetic Materials; Genome; Goals; Hybrids; Inherited; Lead; Link; Meiosis; Microtubules; Modeling; Molecular; Molecular Abnormality; Molecular Evolution; Mus; Pathway interactions; Post-Translational Protein Processing; Pregnancy loss; Process; Proteins; Recurrence; Regulation; Reproductive Biology; Satellite DNA; System; Testing; Tubulin; Variant; Work; centromere protein A; cost; egg; fitness; mouse model; optogenetics; recruit; reproductive fitness; segregation; sperm cell; theories; transmission process; zygote

The seemingly straightforward function of the centromere in directing chromosome segregation is difficult to reconcile with multiple complexities of the underlying molecular machinery, particularly rapid evolution of both centromere DNA and proteins and seemingly redundant pathways linking the DNA to spindle microtubules. This project focuses on centromere drive as a key to unlocking centromere complexity. Selfish centromere DNA sequences bias their transmission to the egg in female meiosis, while centromere proteins evolve to suppress fitness costs of drive while maintaining essential centromere functions. Our recent work determined how selfish centromeres interact with spindle microtubules to bias their segregation. We developed mouse model systems exploiting natural variation in mouse centromere DNA, defined tubulin detyrosination as the key post-translational modification creating meiotic spindle asymmetry, showed that microtubule-destabilizing proteins act as drive effectors exploited by selfish centromeres, established an integrated model for both drive and suppression, and sequenced Murinae genomes for molecular evolution analyses to identify rapidly evolving centromere proteins. Our progress represents crucial steps towards understanding the centromere drive conflict but leaves key gaps in our understanding of drive and suppression and centromere protein evolution, which are addressed in this proposal. First, we will determine how selfish centromeres interact with an asymmetric spindle to bias their segregation. Our previous findings suggest a hypothesis that we will test by manipulating microtubule destabilizing activities at centromeres in live cells, using chemical optogenetic approaches that we developed. Second, we will test whether genetically different centromeres differentially recruit centromere proteins, a central but untested component of the centromere drive theory. Using hybrid mouse zygotes with divergent maternal and paternal centromere satellite DNA sequences as a model system, we will determine if rapidly evolving centromere protein interact differentially with different centromere DNA sequences. Third, we will test for reproductive fitness costs associated with functional differences between centromeres, taking advantage of our hybrid mouse model systems in which paired homologous chromosomes in meiosis have divergent centromeres. Fourth, we will test the concept that centromere proteins have evolved to suppress costs due to functional differences between centromeres, which has been the most challenging part of the drive theory to address experimentally. With tractable experimental systems, a mechanistic model for drive and suppression, and molecular evolution analyses of centromere proteins in place, we will address this challenge by testing whether recurrent changes in rapidly evolving centromere proteins have functional implications consistent with our model. Overall, by investigating centromeres in the context of genetic conflict, this project represents a unique contribution to studies of chromosome segregation and inheritance, with broad consequences for reproductive biology and chromosome evolution.

着丝粒在指导染色体分离中的功能看似简单，但很难解释。 与潜在分子机制的多重复杂性相协调，特别是两者的快速进化 着丝粒DNA和蛋白质以及连接DNA和纺锤体微管的看似冗余的途径。 这个项目的重点是着丝粒驱动器作为解锁着丝粒复杂性的关键。自私着丝粒 在雌性减数分裂中，DNA序列偏向于将其传递到卵子，而着丝粒蛋白则进化为 抑制驱动器的适应性成本，同时保持基本的着丝粒功能。我们最近的工作决定了 自私的着丝粒是如何与纺锤体微管相互作用以偏置它们的分离的。我们开发了老鼠 利用小鼠着丝粒DNA中的自然变异的模型系统，将微管蛋白脱酪氨酸定义为关键 翻译后修饰造成减数分裂纺锤体不对称，表明微管不稳定 蛋白质作为驱动效应物被自私着丝粒利用，建立了驱动效应物和驱动效应物的综合模型， 并对鼠科基因组进行测序，进行分子进化分析， 进化中的着丝粒蛋白我们的进展代表了理解着丝粒的关键步骤 驱动冲突，但在我们对驱动和抑制以及着丝粒蛋白的理解中留下了关键空白 这些变化在本提案中得到了解决。首先，我们将确定自私的着丝粒如何与 一个不对称的纺锤体来偏置它们的分离。我们之前的发现提出了一个假设，我们将通过以下方式进行测试： 使用化学光遗传学在活细胞中的着丝粒处操纵微管去稳定化活性， 我们开发的方法。第二，我们将测试遗传上不同的着丝粒是否差异 招募着丝粒蛋白质，这是着丝粒驱动理论的核心但未经检验的组成部分。使用混合 具有不同的母本和父本着丝粒卫星DNA序列的小鼠合子作为模型系统， 我们将确定快速进化的着丝粒蛋白质是否与不同的着丝粒DNA有差异地相互作用， 序列的第三，我们将测试与功能差异相关的生殖健康成本， 着丝粒，利用我们的杂交小鼠模型系统，其中配对的同源染色体 在减数分裂中有分叉的着丝粒。第四，我们将测试着丝粒蛋白进化的概念， 抑制由于着丝粒之间的功能差异而产生的成本，这是最具挑战性的 驱动理论的一部分，以解决实验。有了易处理的实验系统，一个机械模型 对于驱动和抑制，以及着丝粒蛋白的分子进化分析，我们将讨论 通过测试快速进化的着丝粒蛋白中的经常性变化是否具有功能性， 与我们的模型一致。总的来说，通过在遗传冲突的背景下研究着丝粒， 该项目对染色体分离和遗传的研究做出了独特的贡献， 生殖生物学和染色体进化的后果。