Characterization:novel genotoxic stress-regulated gene

表征：新型遗传毒性应激调节基因

• 批准号: 7229934
• 负责人: M. SAEED SHEIKH
• 金额: $ 18.45万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7229934
• 关键词: Affect; Amino Acid Motifs; Apoptosis; Binding; Binding Sites; CREB1 gene; Ca(2+)-Calmodulin Dependent Protein Kinase; Calcineurin; Calcium-Binding Proteins; Calmodulin; Cells; Code; Colon; Colon Carcinoma; Colonic Neoplasms; Complex; DNA Damage; Development; Down-Regulation; Event; Genes; Genotoxic Stress; Genus Cola; Human; Mediating; Mediator of activation protein; Messenger RNA; Molecular; Names; Normal tissue morphology; Numbers; Pathway interactions; Protein Overexpression; Protein p53; Proteins; Regulatory Element; Relative (related person); Research Personnel; Role; Sequence Analysis; Signal Pathway; Signal Transduction; Specimen; Stress; TP53 gene; Testing; Tissue Microarray; Transcriptional Activation; Tumor Markers; Up-Regulation; environmental agent; insight; mRNA Expression; novel; programs; promoter; protein expression; response; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Cells are constantly exposed to a variety of environmental agents some of which induce DNA damage i.e. genotoxic stress. Cellular responses to genotoxic stress are complex and therefore, more studies are needed to better understand the mechanisms that control such responses. Here we propose to characterize a novel gene, which we have named PIQ (p53-regulated IQ protein) that codes for an IQ motif protein. IQ motifs promote protein interactions with calmodulin (CaM). CaM is a calcium-binding protein that controls several important signaling events. Evidence presented here show that PIQ does indeed bind to CaM. Furthermore, PIQ mRNA is overexpressed in primary colon tumors when compared with matching normal tissues and that PIQ is down-regulated in response to genotoxic stress and p53 activation. PUMA is a key mediator of p53- dependent genotoxic stress-induced apoptosis and our results indicate that PIQ down-regulates PUMA promoter expression. Importantly, PUMA promoter harbors regulatory elements that are predicted to be regulated by CaM-dependent signaling pathways. We, therefore, propose that in unstressed cells, PIQ may negatively regulate PUMA expression by interfering with CaM-dependent signaling events and PIQ downregulation following genotoxic stress serves to promote PUMA upregulation partly via CaM-dependent pathways. Our overall hypothesis is that PIQ is a negative modulator of apoptosis and that higher levels of PIQ expression noted in colon cancer may alter the threshold of apoptosis and consequently contribute in part to colon tumorigenesis. Three specific aims are proposed here to further characterize PIQ in order to elucidate its role in cellular response to genotoxic stress in general and in the development and/or progression of colon cancer in particular. Specific Aim 1 is to investigate the role of PIQ during p53 and genotoxic stress-induced apoptosis. Specific Aim 2 is to investigate the mechanism by which PIQ negatively regulates PUMA promoter expression. Specific Aim 3 is to analyze PIQ expression at the mRNA and protein levels in a larger pool of primary colon tumors and their matching normal tissues and to evaluate a relationship between tumor PIQ-status and the clinicopathologic features.

描述(由申请人提供)：细胞经常暴露在各种环境因素中，其中一些会导致DNA损伤，即遗传毒性应激。细胞对遗传毒性应激的反应是复杂的，因此，需要更多的研究来更好地了解控制这种反应的机制。在这里，我们建议描述一个新的基因，我们将其命名为PIQ(P53调节的IQ蛋白)，它编码一个IQ基序蛋白。IQ基序促进蛋白质与钙调蛋白(CaM)的相互作用。CaM是一种钙结合蛋白，控制着几个重要的信号事件。这里提供的证据表明，PIQ确实与CaM有约束力。此外，与匹配的正常组织相比，PIQ在原发结肠肿瘤中过表达，并且PIQ在基因毒性应激和P53激活的反应中下调。PUMA是P53依赖的基因毒性应激诱导细胞凋亡的关键介质，我们的结果表明PIQ下调PUMA启动子的表达。重要的是，PUMA启动子含有被预测为受CaM依赖的信号通路调控的调控元件。因此，我们认为，在非应激细胞中，PIQ可能通过干扰CaM依赖的信号事件来负向调节PUMA的表达，而遗传毒性应激后PIQ的下调部分通过CaM依赖的途径促进PUMA的上调。我们的总体假设是PIQ是细胞凋亡的负性调节因子，结肠癌中PIQ的高水平表达可能改变了细胞凋亡的阈值，从而在一定程度上促进了结肠癌的发生。这里提出了三个特定的目标，以进一步描述PIQ，以阐明其在细胞对遗传毒性应激反应中的作用，特别是在结肠癌的发生和/或进展中的作用。具体目的1是研究PIQ在P53和基因毒性应激诱导的细胞凋亡中的作用。特异性目的2是研究PIQ负性调控PUMA启动子表达的机制。具体目的3是分析在较大的原发结肠肿瘤及其匹配的正常组织中PIQ在mRNA和蛋白水平的表达，并评估肿瘤PIQ状态与临床病理特征的关系。