Arabidopsis 2010: Defining the Role of Nurse Cells in the Propagation of Transposable Element Epigenetic Silencing

拟南芥 2010：定义护士细胞在转座元件表观遗传沉默传播中的作用

• 批准号: 1020499
• 负责人: R Keith Slotkin
• 金额: $ 47.8万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1020499&HistoricalAwards=false
• 关键词: Arabidopsis; 2010; Defining; Role; Nurse

The DNA in multicellular organisms does not exclusively code for genes. Rather, most organisms' genome, including humans, is also composed of ancient viruses and other parasites call 'jumping genes' or transposable elements (TEs). TEs are fragments of DNA that have the ability to move from one location to another in the genome. When active, TEs have the potential to jump into genes and generate mutations, chromosome breakage and genomic instability. To inhibit the formation of new mutations associated with active TEs, plants, animals and fungi possess a mechanism to suppress and silence TE activity. This mechanism is based on degradation of TE RNA transcripts into TE small RNAs. These TE small RNAs result in the marking of the TE DNA with a molecular flag (such as DNA methylation or post-translational histone modification) that tells the cell to silence the TE. This ?flag? or gene regulatory information on the DNA can be passed through cell division without being reset in an event termed epigenetic inheritance. In plants (and in some cases animals), this information can also be inherited from one generation to the next, helping offspring determine what protein coding regions of DNA are genes and should be expressed, and which are TEs and should be silenced. This project aims to determine how epigenetic information is passed from one generation to the next.In flowering plants, each pollen grain consists of sperm cells and a non-germinal nurse cell termed the pollen vegetative cell. The sperm cells depend on the pollen vegetative cell for delivery to the female egg, but only the DNA of the sperm cells is passed on to the next generation. The nucleus of the pollen vegetative cell undergoes a loss of epigenetic silencing of TEs, resulting in an increase in TE RNA and some new TE small RNAs. In the model flowering plant Arabidopsis thaliana, investigation will focus on 1) whether TE reactivation in the pollen vegetative cell influences the silenced state of sperm cell TEs, and 2) if the increased TE small RNAs in the pollen grain help to reinforce TE silencing in the next generation. 3) Research will focus on how heritable information is physically passed from the non-germinal pollen vegetative cell to the germinal sperm cells. This research has the potential to shift the understanding of parental nourishment, and how multicellular organisms pass heritable information to their offspring. Broader ImpactsThis project will impact the education, training and enrichment of students at each academic level from middle school to post-doctoral. An educational outreach course is taught annually to middle school students from The Ohio State Young Scholars Program, which specializes in providing academic enrichment and career exploration experiences to racial and ethic minorities under represented in STEM fields. High school students will perform senior research projects in the laboratory in collaboration with The Metro School, part of The Ohio State University STEM Learning Network. Undergraduate students will gain summer educational enrichment and exposure to science as a career option through The Ohio State Research Experience for Undergraduates. Through collaborations with outreach organizations at the middle school and high school levels, as well as diversity programs for undergraduate, graduate and post-doctoral students, this project will serve as an educational tool for the development of new scientists.

多细胞生物中的DNA并不专门编码基因。相反，包括人类在内的大多数生物体的基因组也是由古老的病毒和其他被称为“跳跃基因”或转座因子（TE）的寄生虫组成的。TE是DNA片段，具有从基因组中的一个位置移动到另一个位置的能力。当活跃时，TE有可能跳跃到基因中并产生突变、染色体断裂和基因组不稳定性。为了抑制与活性TE相关的新突变的形成，植物、动物和真菌具有抑制和沉默TE活性的机制。该机制基于TE RNA转录物降解为TE小RNA。这些TE小RNA导致TE DNA带有分子标记（如DNA甲基化或翻译后组蛋白修饰），告诉细胞沉默TE。这个吗旗子？或者DNA上的基因调控信息可以通过细胞分裂传递，而不会在称为表观遗传的事件中被重置。在植物中（在某些情况下也包括动物），这些信息也可以从一代遗传到下一代，帮助后代确定DNA的哪些蛋白质编码区是基因，应该表达，哪些是TE，应该沉默。该项目旨在确定表观遗传信息是如何从一代传递到下一代的。在开花植物中，每个花粉粒由精细胞和一个称为花粉营养细胞的非萌发性营养细胞组成。精子依靠花粉营养细胞传递给雌性卵子，但只有精子的DNA传递给下一代。花粉营养细胞的核经历TE的表观遗传沉默的丧失，导致TE RNA和一些新的TE小RNA的增加。在模式开花植物拟南芥中，研究将集中在1）花粉营养细胞中的TE再激活是否影响精细胞TE的沉默状态，以及2）花粉粒中增加的TE小RNA是否有助于加强下一代的TE沉默。3)研究将集中在遗传信息是如何从非萌发花粉营养细胞物理传递到萌发精子细胞。这项研究有可能改变对父母营养的理解，以及多细胞生物如何将遗传信息传递给后代。更广泛的影响这个项目将影响从中学到博士后的每个学术水平的学生的教育，培训和充实。教育外展课程是每年教中学生从俄亥俄州国家青年学者计划，专门提供学术丰富和职业探索经验，以种族和民族少数在STEM领域的代表。高中生将在实验室与地铁学校合作进行高级研究项目，地铁学校是俄亥俄州州立大学STEM学习网络的一部分。本科生将获得暑期教育丰富和接触科学作为职业选择通过俄亥俄州国家研究经验的本科生。通过与初中和高中一级的外联组织以及本科生、研究生和博士后的多样性方案合作，该项目将成为培养新科学家的教育工具。