Genetic and epigenetic regulation of cranial neural crest differentiation

细胞如何在正确的时间和地点变得特定和分化是一个基本的问题， 发育生物学颅神经嵴细胞（cNCCs）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，通常不受限制的发育潜力， 具有已知的谱系和衍生物，以及定义的基因调控网络。除了基因网络， 表观遗传调节因子可以影响许多靶基因的表达，并可能有助于解释 具有相同基因型的个体之间的遗传率和表型的差异。这很重要，因为 神经嵴发育缺陷是许多人类先天性出生缺陷的基础，例如唇裂伴或 没有腭和许多颅面综合征。因此，了解遗传和表观遗传调控， cNCC发育是理解细胞命运如何决定的关键。我们假设PRDM 旁系同源物通过反向调节下游靶点（包括Wnt）来调节整体基因表达 在一些实施方案中，所述方法包括调节cNCC途径组分的活性，以控制cNCC谱系内软骨/骨分化的时机。 拟议研究的基本原理是，对正常cNCC发展的深入了解将 提供了对正常生物学和神经嵴相关出生缺陷的病因学的见解，其中许多是 被认为是由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 PRDM蛋白在Wnt信号上游起作用以控制cNCC时间的假设 分化成软骨细胞。我们将检验在cNCC中需要PROM旁促活性的假设 细胞自主位于Wnt信号上游以促进软骨细胞的分化。2)测试 假设Prdm3和Prdm16在遗传上相互作用以调节cNCC基因表达， 染色质可及性目的2中，假设Prdm 3和Prdm 16在遗传上与控制基因相互作用 通过特异性地调节cNCC和Wnt基因靶点的转录和染色质修饰来表达。 3)检验Prdm3通过控制基因表达的时间来调节全局基因表达的假设。 Prdm 16的基因组可及性。在目标3中，我们将测试Prdm 3的缺失导致全球性疾病的假设。 通过改变Prdm16在整个过程中的结合，改变cNCC祖基因的染色质状态。 基因组，其控制cNCC分化成软骨细胞的限制。这些研究将 揭示了cNCC在发育过程中如何分化为特定细胞类型的基本信息。的结果 这一建议有可能揭示对cNCC发展的重要新见解，以及这些新见解如何影响cNCC的发展。 过程出错的疾病，希望为治疗策略的设计提供基础 神经嵴相关的先天缺陷

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.