Biophysical Mechanisms of Drosophila Development.

描述（由申请人提供）：多细胞生物的不同形状是在发育过程中通过细胞形状和行为的空间和时间调节变化而建立的。在多细胞生物中，一个主要的形态发生运动是细胞重组以形成细长的头尾体轴。这个保守的过程需要一个惊人的方向性，在这个方向性中，细胞群将它们的运动与身体轴对齐，称为细胞嵌入。上皮组织中的细胞嵌入发生在粘附连接网络的存在下，粘附连接网络在细胞之间传递机械力，并在细胞重排过程中保持细胞建立和破坏接触的完整性。遗传学研究已经提供了对调节细胞命运和行为的生化信号的深入了解，但对于细胞如何感知和响应机械信号，将机械力转化为定向细胞运动，我们知之甚少。在果蝇胚胎中，驱动体轴伸长的极化细胞重排是由收缩肌动球蛋白网络的时空调节所引导的。然而，介导力依赖性肌球蛋白调节的分子机制尚不清楚。这些研究的长期目标是深入了解细胞如何将机械力转化为生化信号，从而在发育过程中产生三维组织结构。本提案的总体目标是表征嵌入细胞中调节肌球蛋白定位的机械转导途径的分子基础，并研究该机制如何影响塑造果蝇体轴的三维细胞行为。我们将使用我们开发的高通量计算方法来分析果蝇胚胎中肌球蛋白的体内定位，并将肌球蛋白动力学与参与收缩性和细胞粘附的其他蛋白质的分布进行比较。我们将使用生物物理，实时成像和定量

DESCRIPTION (provided by applicant): The diverse shapes of multicellular organisms are established during development by spatially and temporally regulated changes in cell shape and behavior. A major morphogenetic movement in multicellular organisms is the reorganization of cells to form the elongated head-to-tail body axis. This conserved process requires a striking directionality in which populations of cells align their movements with the body axes, referred to as cell intercalation. Cell intercalation in epithelial tissues occurs in the presence of a networkof adherens junctions that transmits mechanical forces between cells and maintains its integrity as cells make and break contacts throughout cell rearrangement. Genetic studies have provided insight into the biochemical signals that regulate cell fate and behavior, but much less is known about how cells sense and respond to mechanical signals to translate mechanical forces into directional cell movement. In the Drosophila embryo, the polarized cell rearrangements that drive body axis elongation are guided by the spatial and temporal regulation of contractile actomyosin networks. However, the molecular mechanisms that mediate force-dependent myosin regulation are not well understood. The long-term goal of these studies is to obtain insight into how cells translate mechanical forces into biochemical signals to generate three-dimensional tissue structure during development. The overall objective of this proposal is to characterize the molecular basis of the mechanotransduction pathway that regulates myosin localization in intercalating cells and investigate how this mechanism influences the three-dimensional cell behaviors that shape the Drosophila body axis. We will use high-throughput computational methods we have developed to analyze in vivo myosin localization in the Drosophila embryo and compare myosin dynamics with the distributions of other proteins involved in contractility and cell adhesion. We will use biophysical, live imaging and quantitative computational approaches to characterize the molecular mechanisms that translate mechanical forces into a change in myosin localization. In addition, we will analyze cell shape and behavior in three dimensions during axis elongation and characterize the defects in embryos lacking specific proteins. Mechanical forces have been shown to influence many aspects of tissue development, including blood vessel remodeling, lung branching morphogenesis, and development of the heart, kidney, mammary gland, and bone. These studies will identify the mechanisms by which mechanical forces regulate myosin localization and activity and provide information relevant to the treatment and prevention of human diseases that involve defects in mechanical cell regulation, including atherosclerosis, osteoporosis, and tumor progression to metastasis.