Integration of regulatory networks and subcellular architecture to control the Caulobacter cell cycle

 描述（由申请人提供）：在所有生物体中产生细胞多样性的根本基础是在细胞分裂之前结构和调节蛋白质向细胞极的不对称部署以及随后两个子细胞中基因组的差异读出。新月柄杆菌（Caulobacter crescentus）提供了一个优雅的系统，可以破译控制细胞分化之下的不对称性的完整分子电路。当柄杆菌在其细胞周期中移动时，细胞分化伴随着磷酸信号传导蛋白的不同互补物的极性定位。我们的研究计划的目标转向三个重要的问题：1-极性基质纳米结构域如何动态地重新布线极性磷酸化信号传导途径，以驱动细胞分化和不对称细胞分裂？我们正在通过使用脂质体和微加工固体基质重建极性环境，三维超分辨率成像模式和活细胞中的单分子跟踪，以及创建能够瞬时光诱导细胞极组成重新配置的光遗传突变体来解决这个问题，从而使我们能够直接观察活细胞中空间受限信号级联的重新布线的结果。2-细胞类型特异性信号通路如何引起细胞类型特异性基因表达？我们正在定义完整遗传电路的精致复杂性，该电路使用转录和翻译控制来驱动细胞周期进程，最终在不同细胞命运的子细胞中达到顶峰。3-染色体的组织，复制和分离沿着长轴的细胞作为一个计时器的细胞周期调节转录使用表观遗传机制？我们的目标是整合这些时空调控范式，建立适用于解剖所有生命系统中的不对称性的逻辑。

 DESCRIPTION (provided by applicant): The fundamental basis for the generation of cellular diversity in all organisms is the asymmetric deployment of structural and regulatory proteins to the cell poles prior to cell division and the consequent differential readout of the genome in the two daughter cells. The bacterium Caulobacter crescentus provides an elegant system in which to decipher the complete molecular circuitry that controls the asymmetry that underlies cell differentiation. As Caulobacter moves through its cell cycle, cell differentiation is accompanied by the polar localization of distinct complements of phospho-signaling proteins. The goals of our research program turn on three important questions: 1- How does a polar matrix nanodomain function to dynamically re-wire polar phosphosignaling pathways to drive cell differentiation and asymmetric cell division? We are approaching this question through reconstitution of the polar environment using liposomes and microfabricated solid substrates, three dimensional superresolution imaging modalities and single molecule tracking in living cells, and the creation of optogenetic mutants that enable instantaneous light-induced reconfiguration of the cell pole composition, thereby allowing us to directly observe the consequences of re-wiring a spatially-restricted signaling cascade in a living cell. 2- How do cell-type specific signaling pathways beget cell type-specific gene expression? We are defining the exquisite complexity of the complete genetic circuitry that uses both transcriptional and translation control to drive cell cyce progression culminating in daughter cells of different cell fate. 3- How does chromosome organization, replication and segregation along the long axis of the cell serve as a timer of cell cycle-regulated transcription using epigenetic mechanisms? Our goal is to integrate these spatiotemporal regulatory paradigms to establish the logic that is applicable to the dissection of asymmetry in all living systems.