Interplay between mechanical tension and cytoskeletal organization in cell separation at compartment boundaries in Drosophila

果蝇隔室边界细胞分离中机械张力与细胞骨架组织之间的相互作用

• 批准号: 273663197
• 负责人: Professor Dr. Christian Dahmann
• 金额: --
• 依托单位: Professur für Systembiologie und Genetik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/273663197?language=en
• 关键词: Interplay; between; mechanical; tension; cytoskeletal

The formation of straight lineage restrictions (compartment boundaries) between cells of different fates or functions is an important strategy of animal development to pattern tissues. The straightness of compartment boundaries in proliferating and morphogenetically active tissues is challenged by cell intercalations that lead to cell intermingling. Cell junctions along compartment boundaries are characterized by a local increase of mechanical tension as compared to cell junctions in the bulk of the tissue. Computer simulations indicate that this local increase in cell bond tension results in a bias of junctional rearrangements during cell intercalations that maintains the straight alignment of cell junctions along compartment boundaries. However, how mechanical tension is increased at cell junctions along compartment boundaries and whether the local increase in mechanical tension is required to bias junctional rearrangements and thus to maintain the characteristically straight compartment boundary shape remains unknown.The compartment boundary separating anterior and posterior cells of the Drosophila pupal abdominal epidermis is a useful system to analyze the mechanisms underlying compartment boundaries. Cells in this tissue are amenable to live imaging, genetic manipulation, and force measurements. In the current funding period of the SPP1782, we have shown that increased mechanical tension at this compartment boundary can be separated into an initiation phase and a maintenance phase. The initiation phase, when the first junctions between anterior and posterior cells are formed, correlates with elevated levels of F-actin and non-muscle Myosin II and is independent of transcriptional regulation. During the maintenance phase, non-muscle Myosin II is no longer elevated, but increased mechanical tension depends on transcription. This proposal has two aims. First, to analyze the mechanisms by which mechanical tension is increased during the initiation phase. To achieve this aim, we will analyze the subcellular trafficking and recruitment of Myosin II motor proteins using a combination of genetics and live imaging. Second, to analyze the requirement of increased mechanical tension to bias cell rearrangement during cell intercalations and thus to maintain the straight compartment boundary shape. To achieve this aim, we will use an optogenetic method to locally decrease mechanical tension at cell junctions along the compartment boundary.We expect that our results will provide novel insights into the mechanisms by which mechanical tension at cell junctions is regulated and by which this regulation influences cell behavior during tissue development.

不同命运或功能的细胞之间形成直线谱系限制（区室边界）是动物发育形成组织模式的重要策略。增殖和形态发生活跃的组织中隔室边界的直线性受到导致细胞混合的细胞嵌入的挑战。与大部分组织中的细胞连接相比，沿区室边界的细胞连接的特征在于机械张力的局部增加。计算机模拟表明，细胞键张力的局部增加导致细胞嵌入过程中连接重排的偏差，从而保持细胞连接沿区室边界的直线排列。然而，如何在沿隔室边界的细胞连接处增加机械张力，以及是否需要局部增加机械张力来偏向连接重排，从而维持特征性的直隔室边界形状。分隔果蝇蛹腹部表皮的前细胞和后细胞的隔室边界是分析隔室边界机制的有用系统。该组织中的细胞适合实时成像、基因操作和力测量。在 SPP1782 当前的资助期内，我们已经证明，该隔室边界处增加的机械张力可以分为启动阶段和维持阶段。起始阶段，即前细胞和后细胞之间第一个连接形成时，与 F-肌动蛋白和非肌肉肌球蛋白 II 水平升高相关，并且独立于转录调节。在维持阶段，非肌肉肌球蛋白 II 不再升高，但机械张力的增加取决于转录。该提案有两个目的。首先，分析启动阶段机械张力增加的机制。为了实现这一目标，我们将结合遗传学和实时成像来分析肌球蛋白 II 运动蛋白的亚细胞运输和招募。其次，分析在细胞嵌入过程中增加机械张力对偏置细胞重排的要求，从而保持笔直的隔室边界形状。为了实现这一目标，我们将使用光遗传学方法局部降低沿隔室边界的细胞连接处的机械张力。我们期望我们的结果将为调节细胞连接处的机械张力的机制以及这种调节影响组织发育过程中的细胞行为的机制提供新的见解。