Mechanisms of Commitment in Eukaryotic Cell Differentiation

真核生物细胞分化的调控具有基础性意义，在再生医学和生物医学的许多方面都具有广泛的应用潜力。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的或与之相关。长期以来，人们就知道真核细胞的分化依赖于转录因子。然而，控制这些转录因子在生理条件下调节分化不可逆承诺的调节电路在很大程度上是未知的。对于自20世纪70年代初以来一直悬而未决的基本机械原理，甚至还有两种相互矛盾的观点：(1)得到证实的、但很受欢迎的分子事件循序渐进的假设受到了动态系统观点的挑战，(2)动态系统观点认为，由于潜在调控电路的随机性和非线性行为，承诺和分化发生在通过所谓的沃丁顿景观的替代路线上。我们采取了一种全新的、完全非常规的方法来解决这一长期存在的争议。我们的项目依赖于对一个相同的巨细胞进行重复采样，以获得真实的单细胞时间序列。对同一细胞的重复采样对于明确解释随时间变化的基因表达是至关重要的。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，以解决与不可逆承诺和分化相关的分子事件。如提案的图2所示，我们将在确定承诺点方面做出根本贡献，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替代基本机制。

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.