Genomic Analysis into Transcriptional Regulation of Cell Identity

项目摘要/摘要 生物体中的每一个细胞都有几乎完全相同的基因组信息，但体内的细胞 进化成截然不同的细胞身份。例如，一个细胞是如何变成肝细胞的 另一个细胞变成皮肤细胞？这种终末分化为不同类型的细胞是由于正确的 该细胞类型的转录调控。转录因子(TF)是一种调节蛋白质，可以结合 到特定的DNA序列，反应元件，以打开或关闭该细胞类型的基因。贯穿始终 在发育过程中，转录因子导航细胞的染色质景观并结合反应元件， 整合生理和基因特异性线索，指导精确的基因调控网络。至关重要的是 Tf行动是识别正确的响应元素并随后对其进行适当的调节 靶基因，而不影响邻近基因的调节。然而，TF如何识别 正确的反应元件和靶基因还没有被很好地理解。转铁蛋白基因突变及其反应 元素会导致广泛的人类疾病，从而了解这些基本的 转录因子的保真度对我们理解人类健康至关重要。我们的长期目标是 Tf反应元件识别和靶基因识别机制的研究 本能的细胞类型。线虫提供了一个独特的机会来研究转铁蛋白的调节，因为它 紧凑的基因组。线虫的基因间距离平均为2kBP，这使得更容易 由于基因组复杂性降低，反应元件与靶基因的相关性虽然可能 需要有效的机制来屏蔽异常的转铁蛋白作用。在这项建议中，我们使用了一个经过充分研究的 核激素受体NHR-25与两个哺乳动物同源基因NR5A1/SF-1和NR5A2/SF-2，TO 询问转铁蛋白结合和细胞类型特异性靶基因调控。我们将通过一个 基因组和基因技术的结合，开发新的基因组编辑方法，染色质 线虫的结合分析和独特的基因组特征。这些实验将提供对 在培训本科生时，TF如何识别他们的反应元件和靶基因 尖端的基因组技术。

Project Summary/Abstract Every single cell in an organism has almost the exact same genomic information, yet cells in the body develop into vastly different cell identities. For example, how does one cell become a liver cell and another cell become a skin cell? This terminal differentiation into distinct cell types is due to correct transcriptional regulation for that cell type. Transcription factors (TFs) are regulatory proteins that bind to specific sequences of DNA, response elements, to turn on or off genes for that cell type. Throughout development, TFs navigate the chromatin landscape of the cell and bind response elements, integrating physiological and gene-specific cues, directing precise gene regulatory networks. Critical to TF action is recognition of the correct response element and subsequent regulation to its appropriate target gene, while not affecting the neighboring genes’ regulation. However, how a TF recognizes the correct response element and target gene is not well understood. Mutations in TFs and their response elements result in a wide array of human diseases, thus understanding these basic mechanisms of transcription factor fidelity is critical to our understanding of human health. Our long-term goal is to characterize the mechanism of TF response element recognition and target gene recognition in dinstinct cell types. C. elegans provides a unique opportunity to study TF regulation due to its compact genome. Intergenic distance in C. elegans is on average 2 Kbp, which allows for easier correlation of response element to target gene due to the reduced genomic complexity while likely requiring efficient mechanism to shield aberrant TF action. In this proposal we use a well-studied nuclear hormone receptor, NHR-25, with two mammalian orthologs, NR5A1/SF-1 and NR5A2/SF-2, to interrogate TF binding and cell-type specific target gene regulation. We will do so through a combination of genomic and genetic techniques, exploiting new genome editing methods, chromatin binding assays, and unique genomic features of C. elegans. These experiments will provide insight into how TFs recognize their response element and target gene while training undergraduate scientists in cutting-edge, genomic techniques.