Mechanisms for Measuring the Nucleocytoplasmic Ratio in Early Embryogenesis

早期胚胎发生中核质比率的测量机制

• 批准号: 8635910
• 负责人: Shelby Alexander Blythe
• 金额: $ 5.7万
• 依托单位: PRINCETON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8635910
• 关键词: Accounting; Architecture; Arginine; Biological; Biological Assay; Biological Process; Cell Growth Processes; Cell Nucleus; Cell Proliferation; Cell Size; Cell division; Cells; Chromatin; Complex; Coupled; Coupling; Data; Defect; Development; Diploidy; Dose; Drosophila genus; Drosophila melanogaster; Embryo; Embryonic Development; Ensure; Event; Fertilization; Fibrinogen; Gene Activation; Gene Expression; Genetic; Genetic Transcription; Genetic Translation; Genome; Genomic DNA; Global Change; Goals; Hand; Histones; Homeostasis; Hour; Investigation; Logic; Maternal Messenger RNA; Measurement; Measures; Methylation; Modeling; Modification; Molecular; Monitor; Phenotype; Process; Property; Regulation; Regulation of Cell Size; Research; Research Project Grants; Role; System; Testing; Time; Tissues; Translations; Work; biological systems; cell growth; chromatin modification; genome-wide; loss of function; mRNA Expression; mutant; prevent; stem

DESCRIPTION (provided by applicant): One fundamental property of biological systems is the coordination of cellular proliferation with the regulation of cell size. This coordination ensures that cells grow to a minimum size prior to dividing and functions as a checkpoint to prevent unrestricted proliferation. While it is not fully understood how cells measure their size, it has lng been appreciated that the determination of cell size is coupled to the ratio of genomic DNA to cytoplasmic volume. This indicates that there exists a biological mechanism for measuring this nucleo-cytoplasmic (N:C) ratio, but the components of this mechanism are currently unknown. This research project proposes to use the study of the maternal to zygotic transition of the fruit fly Drosophila melanogaster as a model to understand further the mechanism of N:C ratio measurement. Early embryos couple the transition from maternal to zygotic control of development to the measurement of the N:C ratio. This transition results in global changes in embryonic gene expression, stemming, in part, from coordinated activities of both translation-regulatory and chromatin modifying mechanisms. However, a precise account of the mechanism underlying this coordination has been hampered by a paucity of mutants that specifically disrupt this process. The proposed investigation will examine the function of two recently identified Drosophila mutants with potential defects in N:C ratio measurement (dfmr1/capr and valois), and use these factors as a molecular entry point to test two models for quantifying the N:C ratio. I propose to investigate the mechanisms regulating the measurement of the N:C ratio in early Drosophila embryos by exploring the cause of the mutant phenotypes of valois and dfmr1/capr. Since valois and dfmr1 have been shown to interact with additional factors, I propose to test whether loss of function for these partners uncovers additional mutants with putative defects in N:C ratio measurement. With these mutants in hand, I will measure the effect of these defects on the temporal control of zygotic gene activation, using an assay developed in the Wieschaus lab that distinguishes N:C ratio-dependent and -independent effects. Finally, I will test whether mutants of this class interact physically and genetically in order to understand further the regulatory logic underlying this phenotypic class of mutants. I propose two models for quantification of the N:C ratio by translation- or chromatin-coupled mechanisms. By further investigation of dfmr1/capr-dependent translational control of maternal mRNA expression, and valois-dependent chromatin modification, I will examine two candidate mechanisms for measuring the N:C ratio. This project will therefore expand the understanding both of early developmental regulatory systems, and of a fundamental mechanism for measuring cellular size.

描述（由申请人提供）：生物系统的一种基本特性是细胞增殖与细胞大小调节的协调。这种协调可确保细胞在分裂之前生长至最小尺寸，并作为检查点起作用，以防止不受限制的增殖。虽然尚未完全了解细胞如何测量其大小，但已意识到，细胞大小的测定与基因组DNA与细胞质体积的比率耦合。这表明存在一种生物学机制，用于测量该核质质（N：C）的比率，但是该机制的组成部分目前尚不清楚。该研究项目建议利用果蝇果蝇的孕产妇向二卵形过渡作为模型，以进一步了解N：C比率测量的机制。早期胚胎将从母体对发育的二元控制到N：C比的测量。这种过渡导致胚胎基因表达的全球变化，部分原因是翻译调节和染色质修饰机制的协调活性。但是，对这种协调的机制的确切说明受到了特异性破坏该过程的突变体的匮乏的阻碍。拟议的研究将检查两个最近确定的果蝇突变体的功能，具有N：C比测量的潜在缺陷（DFMR1/CAPR和VALOIS），并将这些因子用作分子入口点，以测试两个模型，以量化N：C比。我建议通过探索Valois和DFMR1/CAPR的突变表型的原因来研究早期果蝇胚胎中N：C比的测量机制。由于已经证明Valois和DFMR1与其他因素相互作用，因此我建议测试这些伴侣的功能丧失是否在N：C比值测量中发现了其他假定缺陷的突变体。借助这些突变体，我将使用Wieschaus Lab中开发的测定方法来衡量这些缺陷对合子基因激活的时间控制的影响，该测定区分N：C比率依赖性和非依赖性效应。最后，我将测试该类别的突变体是否在身体和遗传上相互作用，以进一步了解这种表型突变体的调节逻辑。我提出了两个模型，用于通过翻译或染色质耦合机制定量N：C比率。通过进一步研究母体mRNA表达的DFMR1/CAPR依赖性翻译控制和valois依赖性染色质修饰，我将检查两种测量N：C比的候选机制。因此，该项目将扩大对早期发育调节系统的理解，以及测量细胞大小的基本机制。

项目成果

Zygotic genome activation triggers the DNA replication checkpoint at the midblastula transition.

• DOI: 10.1016/j.cell.2015.01.050
• 发表时间: 2015-03-12
• 期刊: Cell
• 影响因子: 64.5
• 作者: Blythe SA;Wieschaus EF
• 通讯作者: Wieschaus EF

Posttranslational control of Cdc25 degradation terminates Drosophila's early cell-cycle program.

• DOI: 10.1016/j.cub.2012.11.029
• 发表时间: 2013-01-21
• 期刊: CURRENT BIOLOGY
• 影响因子: 9.2
• 作者: Di Talia, Stefano;She, Richard;Blythe, Shelby A.;Lu, Xuemin;Zhang, Qi Fan;Wieschaus, Eric F.
• 通讯作者: Wieschaus, Eric F.

Establishment and maintenance of heritable chromatin structure during early Drosophila embryogenesis.

• DOI: 10.7554/elife.20148
• 发表时间: 2016-11-23
• 期刊: eLife
• 影响因子: 7.7
• 作者: Blythe SA;Wieschaus EF
• 通讯作者: Wieschaus EF