Modulation of Oncogenesis by E1A--Role of CtBP and CtIP

E1A 对肿瘤发生的调节——CtBP 和 CtIP 的作用

• 批准号: 6324435
• 负责人: GOVINDASWAMY CHINNADURAI
• 金额: $ 22.77万
• 依托单位: SAINT LOUIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6324435
• 关键词: Adenoviridae; athymic mouse; binding proteins; cell transformation; enzyme activity; gamma radiation; gene mutation; genetic transcription; matrix assisted laser desorption ionization; metastasis; neoplasm /cancer genetics; oncoproteins; phosphoproteins; protein kinase; protein protein interaction; radiation genetics; retinoblastoma protein; transcription factor; viral carcinogenesis; virus genetics; virus protein; western blottings

DESCRIPTION: (Adapted from the Investigator's abstract): The second exon of adenovirus EIA negatively modulates in vitro cell transformation, tumorigenesis and tumor metastasis. These activities of exon 2 are encoded within a short region located near the C-terminus of BIA. Mutations within this region confer a hyper-transforming phenotype on EIA. The oncogenesis restraining activities of the C-terminal region of EIA correlate with the interaction of a 48 kDa cellular nuclear protein, CtBP. CtBP is a transcriptional co-repressor. Through mutational analysis, we will determine if the oncogenesis modulating activity of CtBP is linked to its transcriptional repressor activity. CtBP also interacts with a cellular protein CtIP via a CtBP-binding motif, PLDLS. Our hypothesis predicts that interaction of CtIP with CtBP antagonizes the activities of CtBP and that the C-termninus of EIA may suppress tumorigenesis by disrupting the CtBP/CIIP complex. We hypothesize that the activity of a cellular repressor that functions through the CtBP corepressor may be altered by CtIP or E1A exon 2. We will determine the effects of overexpression of CtIP or EtA on the activity of a model human cellular repressor ZEB. CtBP is a phosphoprotein. We will identify the phosphorylation sites and investigate the role of phosphorylation on CtBP functions. In preliminary studies, we have observed that CtBP interacts with the p70 subunit of DNA-dependent protein kinase (DNA-PK). We will determine if CtBP is a target for DNA-PK. Our hypothesis predicts that an oncogenic stimulus would enhance complex formation between CtBP and CtIP. We will test this hypothesis by analyzing the CtBP/CtIP complex by coimmunoprecipitation analysis in cells expressing EtA exon 1. CtIP also interacts with pRb-family tumor suppressor proteins (pRb, p107 and p130) through an Rb-binding site (LXCXE). We hypothesize that the CR2 region ofElA promotes oncogenesis through a novel pathway (in addition to the previously known pRb/E2F pathway) by disrupting complexes of CtIP and pRb-famity proteins. We propose to investigate if the CR2 region of E1A disrupts the pRb/CtIP complex in vivo and leads to oncogenic transformation in cooperation with E2F-l. Thus, our proposed studies should illuminate how a viral oncoprotein, adenovirus EtA, modulates oncogenesis novel pathways that involve cellular proteins CtBP and CtIP.

描述：（改编自研究者摘要）： 腺病毒EIA负性调节体外细胞转化、肿瘤发生 和肿瘤转移。外显子2的这些活性被编码在一个短的 位于BIA的C末端附近的区域。该区域内的突变 在EIA上表现为超转化表型。抑癌活性 EIA的C-末端区域与48 kDa的 细胞核蛋白。CtBP是一种转录辅阻遏物。通过 突变分析，我们将确定肿瘤发生调节活性 CtBP的表达与其转录抑制活性有关。CTBP也 通过CtBP结合基序PLDLS与细胞蛋白CtIP相互作用。我们 假设预测CtIP与CtBP的相互作用拮抗 EIA的C-端可能抑制肿瘤的发生 通过破坏CtBP/CIIP复合物。我们假设， 通过CtBP辅阻遏物发挥功能的细胞阻遏物可能被改变 CtIP或E1 A外显子2。我们将确定CtIP过表达的影响， 或EtA对模型人细胞阻遏物ZEB活性的影响。CTBP是一种 磷蛋白我们将确定磷酸化位点，并研究 磷酸化对CtBP功能的作用。在初步研究中， 观察到CtBP与DNA依赖蛋白的p70亚基相互作用， 激酶（DNA-PK）。我们将确定CtBP是否是DNA-PK的靶点。我们 一种假说预测致癌刺激会促进复合物的形成 CtBP和CtIP之间的关系。我们将通过分析CtBP/CtIP来验证这一假设。 复合物通过共免疫沉淀分析在表达EtA外显子1的细胞中。CtIP 也与pRb家族肿瘤抑制蛋白（pRb，p107和p130）相互作用 通过Rb结合位点（LXCXE）。我们假设ElA的CR2区 通过一种新的途径促进肿瘤发生（除了以前的 已知的pRb/E2 F途径）。 我们建议研究E1 A的CR2区域是否破坏pRb/CtIP 复合物在体内，并导致致癌转化的合作， E2F-1。因此，我们提出的研究应该阐明病毒癌蛋白， 腺病毒ETA，调节肿瘤发生的新途径，涉及细胞 蛋白质CtBP和CtIP。