The cell biology of dynamic and stable intercellular bridges in situ

原位动态和稳定细胞间桥的细胞生物学

• 批准号: 1616661
• 负责人: Amy Maddox
• 金额: $ 87.25万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1616661&HistoricalAwards=false
• 关键词: cell; biology; dynamic; stable; intercellular

Every animal living on Earth is a collection of cells. Our human bodies contain trillions of cells. These cell building blocks are so tiny that over 1500 of them would fill a layer the size of the period at the end of this sentence. However, every animal living on Earth has developed from a single, exceptionally large cell, the egg. This large size is important for early development to proceed properly. We are studying the way in which the mother animal's body creates such big cells. We already know that this requires helper cells to donate their contents to the growing egg, via stable connections. Our ongoing research is on the maintenance of the stability of the window-like connections between helper cells and the egg. We are also studying how the connections are closed at the right time, so that the egg is finally autonomous. Education and outreach activities will include mentoring of K12 teachers, development and engagement of 2nd grade students in development, a math-biology hands on lab for undergraduates, and a novel approach for matching trainees with scientists and engineers. Also included are efforts to broaden participation of URM students and women in science.The archetypical animal cell has one nucleus. However, in diverse organisms, this rule is broken by tissues such as syncytia. Syncytia are specialized tissues that contain multiple nuclei connected to a common cytoplasm via intercellular bridges. Syncytia are found in diverse contexts such as fruit fly egg chambers, filamentous fungi, mammalian muscle myotubes and plant seeds. In many animals, the egg- and sperm-producing organs are syncytial, and the maintenance of intercellular connections is essential for fertility. Our central aims are to determine the composition, dynamics and regulation of intercellular bridges that connect developing oocytes (egg cells) to a common syncytial cytoplasm. For the propose studies, the model system will be the egg-producing syncytium of the tiny free-living nematod worm, C. elegans. Egg production in the C. elegans syncytial germline is well described genetically and developmentally but has only begun to be explored with cell biology. The small size and transparency of C. elegans make it amenable to quantitative high-resolution in vivo imaging. In addition, quantitative image analysis, photo- and micro-manipulation, biochemistry, reverse genetics and corroborative modeling will be combined to study intercellular connections. C. elegans is highly suitable for dissecting molecular mechanism due to its well-annotated genome and the ease of protein depletion, and genome editing for fluorescent protein tagging. Syncytial intercellular bridges can be thought of as abortive cell division, wherein the cytokinetic ring failed to separate the daughter cells. Therefore, our vast knowledge about how cells pinch in half during cytokinesis has informed hypotheses about the structure and function of intercellular bridges. The high conservation of cell division machinery predicts our findings will be applicable across phylogeny. Furthermore, the conveyor belt-like arrangement of oocyte development from the distal to the proximal gonad will reveal spatio-temporal correlations that predict causal relationships.

生活在地球上的每一种动物都是细胞的集合。我们的人体含有数万亿个细胞。这些细胞构建块是如此之小，超过1500个可以填满一个层的大小，这个层的大小相当于这句话末尾的句号。然而，生活在地球上的每一种动物都是从一个单一的、特别大的细胞--卵子--发展而来的。这个大尺寸对于早期开发的正确进行是重要的。我们正在研究母兽的身体如何产生如此大的细胞。我们已经知道，这需要辅助细胞通过稳定的连接将其内容物捐赠给生长中的卵子。我们正在进行的研究是关于维持辅助细胞和卵子之间窗口状连接的稳定性。我们还在研究如何在正确的时间关闭连接，以便鸡蛋最终实现自主。教育和推广活动将包括K12教师的指导，二年级学生的发展和参与，本科生的数学生物学动手实验室，以及将受训人员与科学家和工程师相匹配的新方法。 还包括努力扩大URM学生和妇女对科学的参与。典型的动物细胞有一个细胞核。然而，在不同的生物体中，这一规则被合胞体等组织打破。合胞体是一种特殊的组织，它含有多个核，通过细胞间桥连接到一个共同的细胞质。合胞体存在于多种环境中，如果蝇卵室、丝状真菌、哺乳动物肌肉肌管和植物种子。在许多动物中，产生卵子和精子的器官是合胞体，细胞间连接的维持对生育力至关重要。我们的中心目标是确定细胞间桥梁的组成，动力学和调节，连接发育中的卵母细胞（卵细胞）到一个共同的合胞质。对于所提出的研究，模型系统将是微小的自由生活的蠕虫的产卵合胞体。优雅的在C.秀丽线虫合胞体生殖系在遗传和发育方面得到了很好的描述，但只是开始用细胞生物学进行探索。C. elegans使其适合于定量高分辨率体内成像。此外，定量图像分析，照片和显微操作，生物化学，反向遗传学和确证建模将结合起来研究细胞间的连接。C.由于其注释良好的基因组和蛋白质消耗的容易性，以及用于荧光蛋白标记的基因组编辑，线虫非常适合于剖析分子机制。合胞体细胞间桥可以被认为是细胞分裂的失败，其中细胞动力学环不能分离子细胞。因此，我们对细胞在胞质分裂过程中如何收缩成两半的大量知识为关于细胞间桥的结构和功能的假设提供了信息。细胞分裂机制的高度保守性预示着我们的发现将适用于整个胚胎发育。此外，卵母细胞发育从性腺远端到近端的传送带状排列将揭示预测因果关系的时空相关性。