Mechanisms of Commitment in Eukaryotic Cell Differentiation

真核生物细胞分化的调控在再生医学和生物医学的许多方面具有重要的基础和广泛的应用潜力。几乎每一种非传染性慢性疾病都是由细胞分化或基因表达失调引起或与之相关的。长期以来，人们都知道真核细胞的分化依赖于转录因子。然而，在生理条件下控制这些转录因子介导不可逆分化的调控回路在很大程度上是未知的。自20世纪70年代初以来，甚至有两种关于基本机制原理的相互竞争的观点未得到解决：(1)未被证实的，但流行的假设，即分子事件的一个明确的循序渐进的序列，受到(2)动态系统观点的挑战，其中承诺和分化发生在所谓的沃丁顿景观的替代路线上，这是潜在调节电路的随机性和非线性行为的结果。我们采用一种全新的、完全非常规的方法来解决这个长期存在的争议。我们的项目依赖于一个和同一个巨细胞的重复采样，以获得真正的单细胞时间序列。同一细胞的重复取样对于基因表达随时间变化的明确解释至关重要。利用获得的数据集，将研究承诺分化的方法，首次获得直接的实验证据来解决与不可逆承诺和分化相关的分子事件。如图2所示，在提案中，我们将在确定承诺点方面做出根本性贡献，并在我们最近发布的有目的地开发的计算数据处理框架的帮助下，区分如何以完全数据驱动的方式实现承诺的其他基本机制。

The regulatory control of cell differentiation in eucaryotes is of fundamental importance with broad application potential in many aspects of regenerative medicine and biomedicine in general. Almost each non-infectious, chronic disease is caused by or associated with the dysregulation of cell differentiation or gene expression. It is known since a long time that the differentiation of eucaryotic cells depends on transcription factors. However, the regulatory circuits that control these transcription factors under physiological conditions in mediating the irreversible commitment to differentiation are largely unknown. There are even two competing views on the fundamental mechanistic principles that are unresolved since the early 1970ties: (1) The uproven, yet popular assumption of a well-defined step-by-step sequence of molecular events is challenged by (2) the dynamic systems perspective where commitment and differentiation occur on alternative routes through the so-called Waddington landscape as a result of stochasticity and non-linear behaviour of the underlying regulatory circuits. We make a new and entirely unconventional approach to resolve this long-standing controversy. Our project relies on repeated sampling of one and the same giant cell to obtain true single cell time series. Repeated sampling of the same cell is crucial for the unequivocal interpretation of gene expression changes over time. With the obtained data sets, ways to commitment to differentiation will be investigated, obtaining for the first time direct experimental evidence to resolve the molecular events associated with irreversible commitment and differentiation. As shown in Fig. 2, of the proposal, we will make a fundamental contribution in identifying commitment points and, with the help of our recently published purposefully developed computational data processing framework, discriminate alternative basic mechanisms of how commitment is achieved in an entirely data-driven manner.