Cell Fate Determination in the Cerebellum

描述(申请人提供)：神经发育需要在一个紧密订阅的时间序列中产生一系列细胞类型。在这方面，小脑的菱形嘴唇是特别有趣的。虽然最初被认为只产生颗粒细胞，但现在已知它也对各种脑后核以及小脑深部核起作用。我们以前的工作表明，通过Notch和BMP信号之间的相互作用，小脑室区细胞被顺序招募为表达Mathl的菱形唇祖细胞。值得注意的是，遗传命运图谱显示，在菱形嘴唇内表达Mathl的祖细胞是高度瞬时的，因此线性不同的Mathl群体依次产生E10至E12之间的后脑和小脑深核，以及E12至E16之间的小脑颗粒细胞。在这笔赠款的第一部分，我们将探索小脑室区内的哪些人群产生了Mathl阳性的菱形唇祖细胞的序列队列。此外，在这个渐进的诱导期，我们将检查Notch和BMP反应前体的身份和后代。在这个目标的最后部分，我们将检查在菱形嘴唇内是否存在隐蔽的血统隔间。具体地说，我们将确定特定的后脑亚型(例如，Chat-ve后脑神经元)是否在菱形嘴唇的特定内侧区域产生。在这项资助的第二部分，我们测试了我们的假设，即Mathl与三个转录因子Id4、Tbr2和Pax6共同作用，控制菱形嘴唇产生离散神经元亚型的能力。我们将首先检查Mathl在晚期但不是早期的菱形唇部后代中的持久性是否影响他们的能力。接下来，我们将对Id4、Tbr2和Pax6的空或条件性空等位基因进行功能丧失分析。最后，我们将使用诱导功能获得的方法来测试这些基因对细胞的充分性，自主地影响菱形唇祖细胞的命运。总之，这些研究不仅将有助于揭示Mathl如何塑造后脑和小脑的发育，而且还将提供对所研究的下游转录因子如何指导该区域细胞命运的洞察。与公共卫生相关：小脑和后脑功能障碍是导致包括运动障碍、共济失调和自闭症在内的一系列神经疾病的原因。与这些疾病状态有关的关键神经元群体产生于菱形嘴唇内。我们的研究将揭示这些人群产生的机制，从而为找到治疗这些疾病的方法迈出第一步。

DESCRIPTION (provided by applicant): Neural development requires that a series of cell types be produced in a tightly subscribed temporal sequence. In this regard the cerebellar rhombic lip is of particular interest. While originally considered to give rise only to granule cells, it is now known to also contribute to a variety of hindbrain nuclei, as well as the deep cerebellar nuclei. Our previous work demonstrated that through an interplay between Notch and BMP signaling, cerebellar ventricular zone cells are sequentially recruited to become Mathl-expressing rhombic lip progenitors. Remarkably, genetic fate mapping has revealed that the Mathl expressing progenitors within the rhombic lip are highly transient, such that lineally distinct Mathl populations sequentially give rise to hindbrain and deep cerebellar nuclei between E10 and E12 and cerebellar granule cells between E12 and E16. In the first part of this grant we will explore which populations within the cerebellar ventricular zone give rise to the sequential cohorts of Mathl positive rhombic lip progenitors. Furthermore during this progressive induction period, we will examine the identity and progeny derived from Notch versus BMP responsive precursors. In the final part of this aim we will examine whether there exists covert lineage compartments within the rhombic lip. Specifically, we will determine whether specific hindbrain subtypes (e.g. Chat-+ve hindbrain neurons) are produced within a particular medio-lateral domain of the rhombic lip. In the second section of this grant, we test our hypothesis that Mathl acts in conjunction with three transcription factors, Id4, Tbr2 and Pax6 to control the competence of the rhombic lip to produce discrete neuronal subtypes. We will first examine whether the persistence of Mathl in late but not early rhombic lip progeny affects their competence. We will next do a loss of function analysis of either null or conditionally null alleles of Id4, Tbr2 and Pax6. Finally we will use an inducible gain of function approach to test the sufficiency of these genes to cell autonomously affect the fate of rhombic lip progenitors. Together these studies will not only be informative in revealing how Mathl shapes development in the hindbrain and cerebellum but will also provide insight into how the examined downstream transcription factors direct cell fate in this region. Relevance to Public Health: Disfunction in the cerebellum and hindbrain is responsible for a wide spectrum of neurological disorders including dyskinesia, ataxia and autism. Key neuronal populations implicated in these disease states are generated within the rhombic lip. Our studies will reveal the mechanisms by which these populations are generated and thus provide the first step towards finding a cure to these disorders.