Regulation of Kidney-Specific Gene Expression

摘要 MERIT更新的目的是继续我们对肝细胞核因子-1 β（HNF-1β）及其在肝细胞凋亡中的作用的研究。 在肾脏特异性基因表达和囊性肾病中的作用。HNF-1β是一种DNA结合转录因子 调节肾脏和其他上皮器官中组织特异性基因表达的因子。HNF突变- 1β产生先天性异常的肾脏和泌尿道，囊性肾病，常染色体显性遗传 肾小管间质性肾病和遗传性肾小管病。为了阐明这些疾病的发病机制， 我们已经产生了HNF-1β突变小鼠，其表型与在受影响的人类中观察到的表型相似。 对突变小鼠的分析表明，HNF-1β在多囊肾的表达中起着核心作用。 疾病基因，如PKD 2和PKHD 1。在上一个项目期间，我们使用了全基因组ChIP-seq， RNA-seq鉴定直接受HNF-1β调控的转录网络。与新变种一起 在小鼠模型中，这些研究揭示了HNF-1β在调节Wnt信号、cAMP 信号传导、脂质代谢、尿浓度和非编码RNA的表达。初步研究使用 质谱分析显示，HNF-1β与参与染色质重塑的蛋白质、组蛋白 修饰和转录延伸。在下一个项目期间，我们将扩大这项工作，以进一步解开 HNF-1β在肾脏中的作用。具体目标1将使用生物化学研究来解开分子 HNF-1β抑制Wnt途径基因的机制。我们将检验HNF-1β形成的假设， 抑制性染色质环，对组蛋白修饰、染色质重塑和 转录延伸具体目标2将应用小鼠遗传学来阐明Wnt失调的作用 HNF-1β突变表型中的信号传导。我们将确定Wnt途径基因的突变是否是 在HNF-1β突变小鼠中过表达可改善肾功能和结构。总体而言，拟议的研究 将促进我们对基因调控的理解，揭示HNF-1β突变如何产生肾脏 HNF-1β相关性囊性肾病的潜在治疗靶点。

ABSTRACT The purpose of this MERIT renewal is to continue our studies on hepatocyte nuclear factor-1β (HNF-1β) and its roles in kidney-specific gene expression and cystic kidney diseases. HNF-1β is a DNA-binding transcription factor that regulates tissue-specific gene expression in the kidney and other epithelial organs. Mutations of HNF- 1β produce congenital anomalies of the kidney and urinary tract, cystic kidney disease, autosomal dominant tubulointerstitial kidney disease, and inherited tubulopathies. To unravel the pathogenesis of these disorders, we have produced HNF-1β mutant mice that develop phenotypes similar to those seen in affected humans. Analysis of the mutant mice has revealed that HNF-1β plays a central role in the expression of polycystic kidney disease genes, such as PKD2 and PKHD1. During the last project period, we used genome-wide ChIP-seq and RNA-seq to identify transcriptional networks that are directly regulated by HNF-1β. Together with new mutant mouse models, these studies uncovered novel roles of HNF-1β in the regulation of Wnt signaling, cAMP signaling, lipid metabolism, urinary concentration, and expression of noncoding RNAs. Preliminary studies using mass spectrometry revealed that HNF-1β interacts with proteins involved in chromatin remodeling, histone modification, and transcription elongation. In the next project period we will extend this work to further unravel the functions of HNF-1β in the kidney. Specific Aim 1 will use biochemical studies to unravel the molecular mechanisms whereby HNF-1β represses Wnt pathway genes. We will test the hypothesis that HNF-1β forms repressive chromatin loops that exert long-range effects on histone modification, chromatin remodeling, and transcription elongation. Specific Aim 2 will apply mouse genetics to elucidate the roles of dysregulated Wnt signaling in the HNF-1β mutant phenotype. We will determine whether mutations of Wnt pathway genes that are overexpressed in HNF-1β mutant mice improve kidney function and structure. Collectively, the proposed studies will advance our understanding of gene regulation, unravel how mutations of HNF-1β produce kidney abnormalities, and identify potential therapeutic targets for HNF-1β-related cystic kidney diseases.