Cell Fate Determination in the Cerebellum

描述（由申请人提供）：神经发育需要一系列的细胞类型在一个紧密订阅的时间序列中产生。在这方面，小脑菱形唇是特别有趣的。虽然最初认为它只产生颗粒细胞，但现在已知它也有助于各种后脑核以及小脑深部核。我们之前的工作表明，通过Notch和BMP信号之间的相互作用，小脑室带细胞被依次招募成为表达mathl的菱形唇祖细胞。值得注意的是，遗传命运图谱显示，在菱形唇内表达Mathl的祖细胞是高度短暂的，因此线性不同的Mathl群体依次在E10和E12之间产生后脑和小脑深部核，在E12和E16之间产生小脑颗粒细胞。在本基金的第一部分，我们将探讨小脑心室区内的哪些人群会产生Mathl阳性菱形唇祖细胞的序列队列。此外，在这个渐进诱导期，我们将研究Notch与BMP反应性前体的身份和后代。在这个目的的最后一部分，我们将检查是否存在隐蔽的谱系室在菱形唇。具体来说，我们将确定特定的后脑亚型（例如，Chat-+ve后脑神经元）是否在菱形唇的特定中外侧区域产生。在本授权的第二部分，我们验证了我们的假设，即Mathl与三个转录因子，Id4， Tbr2和Pax6一起作用，以控制菱形唇产生离散神经元亚型的能力。我们将首先检查Mathl在晚期而不是早期的菱形唇后代中是否会影响他们的能力。接下来，我们将对Id4、Tbr2和Pax6的空等位基因或条件空等位基因进行功能缺失分析。最后，我们将使用可诱导的功能增益方法来测试这些基因的充分性，以细胞自主影响菱形唇祖细胞的命运。总之，这些研究将不仅在揭示Mathl如何影响后脑和小脑的发育方面提供信息，而且还将为研究下游转录因子如何指导该区域的细胞命运提供见解。与公共卫生的相关性：小脑和后脑功能障碍是导致广泛的神经系统疾病的原因，包括运动障碍、共济失调和自闭症。与这些疾病状态相关的关键神经元群是在菱形唇内产生的。我们的研究将揭示这些群体产生的机制，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.