Developmental regulation of oscillatory expression

 描述（由申请人提供）：脊椎动物分段时钟是一种模型生物振荡器，在发育中的胚胎中产生周期性模式。体节时钟控制着体节发生，即脊椎动物的中胚层被顺序地分成称为体节的节段单位的过程。分割时钟的核心是一个涉及her/Hes转录抑制因子的自抑制负反馈回路。虽然体节发生的“时钟和波前”模型被广泛接受，但时钟调节的许多方面仍不清楚，随着我们检查体内振荡动力学的能力变得更加复杂，其他方面可能会受到挑战。只是在过去的几年里，我们才能够观察到活胚胎中的分割时钟振荡，直到最近，我们才能够以单细胞分辨率这样做。随着我们检测快速生物振荡的能力的提高，越来越多的生物振荡器控制各种细胞反应和细胞命运决定的例子正在被发现，这强调了了解它们是如何被调节的迫切需要。 在这项建议中，我们将集中在表征的顺式调控元件和反式作用的因素，需要在很大程度上研究不足，但关键方面的振荡系统-循环转录衰变。快速的转录周转在像脊椎动物分段时钟这样的振荡系统中是至关重要的，其中每一轮转录之后必须跟随一波转录衰减以维持振荡。我们已经有了一个因子，Pnrc 2，这将大大有助于识别一个环状转录本“衰变复合物”。我们预计，这项工作将广泛影响我们对许多发育背景下RNA周转调控的理解。 快速分子振荡器不仅在发育过程中产生节段性模式，而且在促进神经干细胞的异质性反应，以及使胚胎干细胞偏向不同的细胞命运方面非常重要。此外，Hes 1上调促进横纹肌肉瘤，一种侵袭性儿童癌症。因此，我们对循环调节的了解越多，我们就越有可能开发出有前景的人类疾病治疗方法或疗法。我们建议揭示一个这样的振荡系统，脊椎动物分段时钟，控制振荡动力学的调控机制，元素和因素，并预计我们的工作将影响不同领域的研究，如发育生物学，干细胞生物学，组织工程，并可能癌细胞生物学。

 DESCRIPTION (provided by applicant): The vertebrate segmentation clock is a model biological oscillator that generates periodic pattern in developing embryos. The segmentation clock controls somitogenesis, the process by which the mesoderm of the vertebrate animal is sequentially divided into segmental units called somites. At the core of the segmentation clock is an auto-inhibitory negative feedback loop involving her/Hes transcriptional repressors. Although the `clock and wave front' model of somitogenesis is widely accepted, there are still many aspects of clock regulation that are not understood, and yet other aspects that may be challenged as our ability to examine oscillation dynamics in vivo becomes more sophisticated. It is only over the last few years that we have been able to watch the segmentation clock oscillate in living embryos and only very recently that have we been able to do so with single cell resolution. As our ability to detect rapid biological oscillations improves, more and more examples of biological oscillators controlling diverse cellular responses and cell fate decisions are being discovered, underscoring a critical need to understand how they are regulated. In this proposal, we will focus on characterizing the cis regulatory elements and trans-acting factors required for a largely understudied but critical aspect of oscillatory systems - that of cyclic transcript decay. Rapid transcript turnover is critical in oscillatory systems like the vertebrate segmentation clock, where every round of transcription must be followed by a wave of transcript decay to sustain oscillations. We already have one factor in hand, Pnrc2, which will greatly facilitate the identification of a cyclic transcript "decay complex". We anticipate that this work ill broadly impact our understanding of regulation of RNA turnover in many developmental contexts. Rapid molecular oscillators are not only important for generating segmental pattern during development, but also for promoting heterogeneous responses in neural stem cells, and for biasing embryonic stem cells toward different cell fates. Additionally, Hes1 upregulation promotes rhabdomyosarcoma, an aggressive childhood cancer. Thus, the more we understand cyclic regulation, the more likely we are to develop promising treatments or therapeutics for human disease. We propose to uncover regulatory mechanisms, elements, and factors that control oscillation dynamics in one such oscillatory system, the vertebrate segmentation clock, and anticipate that our work will impact studies in fields as diverse as developmental biology, stem cell biology, tissue engineering, and possibly cancer cell biology.