Genetic and epigenetic regulation of cranial neural crest differentiation

如何在正确的时间和地点指定细胞并进行分化是 发育生物学。脑神经脊细胞(Cncc)是一个很好的模型系统来理解这一点。 由于祖细胞的多能性，通常具有不受限制的发育潜力 具有已知的血统和衍生品，并定义了基因调控网络。除了基因网络， 表观遗传调节剂可以影响许多靶基因的表达，并可能有助于解释 相同基因个体之间的外显性和表型差异。这一点很重要，因为 神经脊发育缺陷是许多人类先天缺陷的基础，例如唇裂或唇裂。 没有上颚和许多头面部综合征。因此，了解基因和表观遗传调控因子 CNCC的发展是理解细胞命运如何决定的关键。我们假设PRDM Paralog通过相反的方式调节下游靶标，包括Wnt，从而调节全球基因表达 途径成分，控制CNCC谱系内软骨/骨分化的时间。 建议进行研究的理由是，深入了解CNCC的正常发展将 提供对正常生物学和神经脊相关出生缺陷的病因的见解，其中许多是 认为是由CNCC异常引起的。我们将在以下具体目标中检验这一假设：1)检验 假设PRDM蛋白作用于Wnt信号的上游以控制CNCC的时间 分化为软骨细胞。我们将测试cNCC中需要PROM Paralog活动的假设 细胞自主地在Wnt信号的上游促进软骨细胞的分化。2)测试 Prdm3和Prdm16基因相互作用调控CNCC基因表达的假说 染色质可及性。在目标2中，假设Prdm3和Prdm16在遗传上相互作用以控制基因 通过调控转录和染色质修饰，特异性地针对CNCC和WNT基因靶点进行表达。 3)检验Prdm3通过控制时间来调节全球基因表达的假设 Prdm16的基因组可及性。在目标3中，我们将检验这样的假设，即Prdm3的丢失导致全球 CNCC前体基因染色质状态的改变--通过Prdm16结合的变化 基因组，控制CNCC向软骨细胞分化的过程。总而言之，这些研究将 揭示cNCC在发育过程中如何分化为特定细胞类型的基本信息。结果是 这项提案有可能揭示对CNCC发展的重要新见解，以及这些 过程在疾病中出错，希望为治疗策略的设计提供基础 神经脊束相关的出生缺陷。

How cells become specified and differentiate at the correct time and place is a fundamental question in developmental biology. Cranial neural crest cells (cNCCs) are an excellent model system to understand this process due to the multipotent nature of the progenitor cells, generally unrestricted developmental potential with known lineage and derivatives, and defined gene regulatory networks. In addition to the gene networks, epigenetic regulators can affect the expression of numerous target genes and may help to explain the differences in penetrance and phenotype between individuals with the same genotype. This is important since defects in neural crest development underlie many human congenital birth defects, such as cleft lip with or without palate and many craniofacial syndromes. Thus, understanding the genetic and epigenetic regulators in cNCC development is key to understanding how cell fate is determined. We hypothesize that PRDM paralogs regulate global gene expression by regulating downstream targets oppositely, including Wnt pathway components, to control the timing of cartilage/bone differentiation within the cNCC lineage. The rationale for the proposed studies is that an in depth understanding of normal cNCC development will provide insights into normal biology and the etiology of neural crest-associated birth defects, many of which are thought to arise from cNCC abnormalities. We will test this hypothesis in the following specific aims: 1) Test the hypothesis that PRDM proteins act upstream of Wnt signaling to control the timing of cNCC differentiation into chondrocytes. We will test the hypothesis PROM paralog activity is required in cNCCs cell autonomously upstream of Wnt signaling to promote differentiation of chondrocytes. 2) Test the hypothesis that Prdm3 and Prdm16 genetically interact to regulate cNCC gene expression and chromatin accessibility. In Aim 2, hypothesis that Prdm3 and Prdm16 genetically interact to control gene expression via regulating transcription and chromatin modification specifically at cNCC and Wnt gene targets. 3) Test the hypothesis that Prdm3 regulates global gene expression by controlling the timing of genomic accessibility of Prdm16. In Aim 3, we will test the hypothesis that loss of Prdm3 leads to global alterations in chromatin state at cNCC progenitor genes via changes in binding of Prdm16 throughout the genome, which controls the liming of cNCC differentiation into chondrocytes. Together, these studies will reveal basic information of how cNCCs differentiate into specific cell types during development. The results of this proposal have the potential to reveal important new insights into cNCC development and how these processes go wrong in disease, with the hope of providing a foundation for the design of therapeutic strategies for neural crest associated birth defects.