Genomic and functional analysis of transcriptome changes in Huntington's Disease

HD基因产物亨廷顿蛋白的外显子1中的CAG重复扩增导致亨廷顿病（HD）， 一种致命的神经退行性疾病，无法治愈或进行神经保护治疗。失调 转录是HD发病机制的主要特征，如使用RNA阵列的大量工作所示 技术，并致力于特定的转录因子及其目标。最近的研究也表明， 表明亨廷顿蛋白在RNA加工中的作用。 关于HD脑组织中基因表达改变的先前工作使用3'偏向基因表达阵列。的 在许多人类疾病，特别是神经变性疾病中， 异常的前体mRNA剪接然而，传统的基因表达技术并不很适合 选择性剪接模式的定量分析，并没有采样罕见的转录。 从我们的初步工作的几个证据表明全球剪接异常的HD。为 例如，我们之前报道过microRNA miR-124在HD大脑中显著减少。Maniatis的作品 及其同事发现，miR-124通过下调- 调节一个重要的组织特异性剪接调节因子，聚嘧啶片段结合蛋白（PTBP 1）。 与miR-124的减少一致，我们有初步证据表明PTBP 1 HD患者样本中的mRNA水平。此外，初步数据表明，基因中的几个外显子 PTBP 1调控的外显子在HD脑中显示相应的外显子包含/排除的变化。入选或 非组成型外显子的排除可对转录物稳定性和蛋白质活性产生显著影响。因此 HD中的转录组改变可能超出上调和下调的基因，包括基因表达的改变。 和蛋白质同种型。在全球范围内对这些事件进行评估将有助于揭示疾病 病理生理学，并且可以鉴定用于治疗的新的药物靶标。在我们的工作中，它包括三个目标，我们 将从鉴定改变的HD转录组，到验证，再到体外和体内研究， 它们与HD表型的相关性。 这些研究联合收割机了Xing实验室的基因组学和生物信息学专业知识以及 罗斯和戴维森实验室这些变化的功能相关性将使用增益和损失来阐明 戴维森和罗斯实验室的功能研究，其中两组都有大量的经验与HD 模型

A CAG repeat expansion in exon 1 of the HD gene product, huntingtin, causes Huntington's disease (HD), a fatal neurodegenerative disease for which there is no cure or neuroprotective treatment. Dysregulation of transcription is a major feature of HD pathogenesis, as indicated by a large body of work using RNA array techniques, and work on specific transcription factors and their targets. More recent studies have also suggested a role for huntingtin in RNA processing. Prior work on gene expression alterations in HD brain tissues used 3' biased gene expression arrays. Of increasing importance in many human diseases, particularly neurodegenerative diseases, is the occurrence of aberrant alternative pre-mRNA splicing. However, conventional gene expression techniques are not well suited to quantitative analysis of alternative splicing patterns, and do not sample rare transcripts well. Several lines of evidence from our preliminary work suggest global splicing abnormalities in HD. For example, we reported earlier that microRNA miR-124 was significantly reduced in HD brains. Work by Maniatis and colleagues showed that miR-124 promotes neuronal-specific alternative splicing events by down- regulating an important tissue-specific splicing regulator, polypyrimidine tract-binding protein (PTBP1). Consistent with the decrease in miR-124, we have preliminary evidence for significantly increased PTBP1 mRNA levels in HD patient samples. Moreover, preliminary data suggest that several exons in genes regulated by PTBP1 show corresponding changes in exon inclusion/exclusion in HD brain. Inclusion or exclusion of non-constitutive exons can have dramatic effects on transcript stability and protein activity. Thus transcriptome alterations in HD may extend beyond up- and down-regulated genes to include changes in gene and protein isoforms. Assessing these events on a global scale for HD will aid efforts to unravel disease pathophysiology, and may identify new drug targets for therapy. In our work, which encompasses 3 aims, we will move from identification of the altered HD transcriptome, to validation, to in vitro and in vivo studies to test their relevance on HD phenotypes. These studies combine the genomics and bioinformatics expertise of the Xing lab and the HD expertise of the Ross and Davidson labs. The functional relevance of those changes will be elucidated using gain and loss of function studies in the Davidson and Ross labs, where both groups have substantial experience with HD models.