Physiological and environmental control of C. elegans germline stem cell mitosis

有丝分裂是一个高度动态的过程，精心安排，以确保复制的基因组在子细胞之间平等分割。尽管有大量关于细胞培养模型中有丝分裂的机制研究，但关于有丝分裂如何发生在原位分裂的细胞中，即在其自然环境中，在活的有机体中，人们知之甚少。特别是，有丝分裂如何适应不同的生理或环境条件在很大程度上是未知的。这种知识差距主要是由于进行活体成像研究的技术挑战，这些研究建立在我们目前对有丝分裂过程的理解上，细胞在原位分裂。我的研究计划将通过使用有丝分裂线虫生殖系干细胞(GSCs)的原位活细胞成像来解决这一差距，以确定环境和组织水平的变化如何影响单个细胞的有丝分裂。在我的博士后研究期间，我开发了第一种在线虫成体生殖系干细胞(GSCs)中原位实时成像有丝分裂的方法，建立了GSCs作为有丝分裂研究的模型，并提供了独特的机会来评估环境条件和组织生理学的操纵如何影响有丝分裂的细胞生物学。我已经证明，调节饮食摄入量或胰岛素信号会影响核心有丝分裂过程的持续时间和保真度，这一过程称为“融合”。根据这些结果，本研究计划将结合高分辨率活细胞成像、定量图像分析和遗传学方法来研究(1)不同生理条件下GSC表达变化的分子基础和(2)调控这些变化的信号机制(S)。我们研究计划的首要目标是发现有丝分裂是如何在生物体的复杂生理环境中发生的，它是如何适应以保持保真度的，以及在一系列生理条件下有丝分裂过程在哪里容易失败。由于大多数线虫基因执行进化上保守的功能，这些结果可能提供对其他生物中有丝分裂的体内调节的洞察，并揭示驱动有丝分裂适应的选择压力。

Mitosis is a highly dynamic process, carefully orchestrated to ensure equal partitioning of the replicated genome between daughter cells. While there are a wealth of mechanistic studies of mitosis in cell culture models, far less is known about how mitosis occurs in cells dividing in situ, i.e. in their native environment, within a living organism. In particular, how mitosis is adapted to different physiological or environmental conditions is largely unknown. This knowledge gap is due primarily to the technological challenge of conducting live imaging studies, which have anchored our current understanding of mitotic processes, on cells dividing in situ. My research program will address this gap by using in situ live cell imaging of mitotic C. elegans germline stem cells (GSCs) to determine how changes at the environmental and organismal level impact mitosis in individual cells. During my postdoctoral fellowship, I developed the first method to live image mitosis in situ in C. elegans adult germline stem cells (GSCs), establishing GSCs as a model for the study of mitosis and affording the unique opportunity to assess how manipulation of environmental conditions and organismal physiology affects the cell biology of mitosis. I have shown that modulating dietary intake or Insulin signaling influences the duration and, likely, the fidelity, of a core mitotic process called "congression". Following on these results, this research program will combine high-resolution live-cell imaging, quantitative image analysis and genetic approaches to investigate (1) the molecular basis for altered GSC congression under different physiological conditions and (2) the signaling mechanism(s) by which these changes are regulated. The overarching goal of our research program is to discover how mitosis occurs in the physiologically complex environment of a living organism, how it is adapted to preserve fidelity and where mitotic processes are prone to fail under a range of physiological conditions. As most C. elegans genes perform evolutionarily conserved functions, these results may provide insight into the in vivo regulation of mitosis in other organisms and uncover selective pressures that have driven mitotic adaptations.