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: 6514350
• 负责人: GOVINDASWAMY CHINNADURAI
• 金额: $ 22.67万
• 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/6514350
• 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：（改编自研究者的摘要）：第二个外显子 腺病毒 EIA 负向调节体外细胞转化、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 该区域位于 BIA C 末端附近。该区域内的突变赋予 EIA 上的超转化表型。抑制肿瘤发生的活性 EIA 的 C 端区域与 48 kDa 的相互作用相关 细胞核蛋白，CtBP。 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是否 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。我们的 假设预测 CtIP 与 CtBP 的相互作用会拮抗 CtBP 的活性以及 EIA 的 C 末端可能抑制肿瘤发生 通过破坏 CtBP/CIIP 复合体。我们假设a的活动 通过 CtBP 辅阻遏物起作用的细胞阻遏物可能会改变 通过 CtIP 或 E1A 外显子 2。我们将确定 CtIP 过度表达的影响 或 EtA 对人类细胞阻遏物 ZEB 模型活性的影响。 CtBP 是 磷蛋白。我们将识别磷酸化位点并研究 磷酸化对 CtBP 功能的作用。在初步研究中，我们有 观察到 CtBP 与 DNA 依赖性蛋白的 p70 亚基相互作用 激酶（DNA-PK）。我们将确定 CtBP 是否是 DNA-PK 的目标。我们的 假设预测致癌刺激会增强复合物的形成 介于 CtBP 和 CtIP 之间。我们将通过分析 CtBP/CtIP 来检验这一假设 在表达 EtA 外显子 1 的细胞中通过免疫共沉淀分析复合物。CtIP 还与 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区域 通过一种新的途径促进肿瘤发生（除了以前的途径） 通过破坏 CtIP 和 pRb-家族蛋白的复合物（已知的 pRb/E2F 途径）。 我们建议调查 E1A 的 CR2 区域是否破坏 pRb/CtIP 体内复杂并导致致癌转化 E2F-l。因此，我们提出的研究应该阐明病毒癌蛋白如何， 腺病毒 EtA，调节肿瘤发生涉及细胞的新途径 蛋白质 CtBP 和 CtIP。