The E2F1 Post-Translational Modification Code

项目摘要 E2 F1转录因子在大多数癌症中通过p16 INK 4A-细胞周期蛋白D-RB的破坏而失调 肿瘤抑制途径，但E2 F1在癌症中发挥的作用是复杂的，因为它可以促进或抑制 肿瘤的发展取决于环境。E2 F1也可以在分子水平上具有相反的活性， 在细胞水平上通过促进增殖或凋亡来激活或抑制转录。此外，委员会认为， E2 F1可以直接刺激DNA修复，而不依赖于其在转录中的作用。这些长期目标 研究的目的是了解E2 F1的各种功能在细胞中是如何调节的，以及每个功能是如何调节的。 活动有助于癌症的发展或抑制。E2 F1被磷酸化、乙酰化， 但这些修饰如何改变E2 F1的活性仍有待研究。 不太了解。该建议基于以下假设： E2 F1被相互作用的蛋白质读取，以调节E2 F1的定位和在DNA修复中的功能， 转录和肿瘤发生。TopBP 1蛋白在磷酸化时特异性结合E2 F1 这种相互作用导致E2 F1被募集到DNA损伤位点。要求1 研究将使用一种新的基因敲入小鼠模型（S29 A），该模型阻断E2 F1磷酸化，以确定E2 F1的表达。 E2 F1及其相关蛋白在DNA位点动态修饰染色质结构中的功能 损坏，便于维修。初步数据表明，E2 F1乙酰化产生了一个结合基序， CBP和p300乙酰转移酶的溴结构域。阻断E2 F1的新型基因敲入小鼠模型 乙酰化将用于研究E2 F1-CBP/p300相互作用如何调节组蛋白乙酰化， 修饰DNA损伤部位的染色质结构以促进修复。这些基因敲入小鼠也将被用于 研究E2 F1乙酰化在调节转录和抑制肿瘤发展中的作用（目的2）。 TDRD 3蛋白被鉴定为E2 F1精氨酸甲基化标记（R109 me）的潜在阅读器。的 将研究TDRD 3在DNA修复和转录中调节E2 F1依赖性功能的作用，如果 因此，将开发一种敲入小鼠模型，以确定这种修饰在调节 肿瘤发生总之，这些研究将揭示E2 F1翻译后修饰密码是如何被阅读的。 各种染色质修饰活性来调节DNA修复和转录。确定这些 E2 F1翻译后修饰影响癌症的发展将揭示新的机会， 调节E2 F1的活性以抑制肿瘤生长并增强治疗效果。

PROJECT SUMMARY The E2F1 transcription factor is deregulated in most cancers through disruptions in the p16INK4A-cyclin D-RB tumor suppressor pathway but the role E2F1 plays in cancer is complex as it can either promote or inhibit tumor development depending on the context. E2F1 can also have opposing activities at the molecular level by activating or repressing transcription and at the cellular level by promoting proliferation or apoptosis. Moreover, E2F1 can directly stimulate DNA repair independent of its role in transcription. A long-term goal of these studies is to understand how the various functions of E2F1 are regulated in the cell and how each activity contributes to the development or suppression of cancer. E2F1 is phosphorylated, acetylated, and methylated in response to DNA damage but how these modifications alter the activities of E2F1 remains poorly understood. This proposal is based on the hypothesis that post-translational modifications on E2F1 are read by interacting proteins to regulate E2F1 localization and functions in DNA repair, transcription and tumorigenesis. The TopBP1 protein specifically binds to E2F1 when it is phosphorylated by the ATM/ATR kinases and this interaction results in the recruitment of E2F1 to sites of DNA damage. Aim 1 studies will use a novel knock-in mouse model (S29A) that blocks E2F1 phosphorylation to determine the function of E2F1 and its associated proteins in dynamically modifying chromatin structure at sites of DNA damage to facilitate repair. Preliminary data demonstrates that E2F1 acetylation creates a binding motif for the bromodomains of the CBP and p300 acetyltransferases. A novel knock-in mouse model that blocks E2F1 acetylation will be used to study how the E2F1-CBP/p300 interaction regulates histone acetylation and modifies chromatin structure at sites of DNA damage to facilitate repair. These knock-in mice will also be used to examine the role of E2F1 acetylation in regulating transcription and suppressing tumor development (Aim 2). The TDRD3 protein was identified as a potential reader of an E2F1 arginine methylation mark (R109me). The role of TDRD3 in regulating E2F1-dependent functions in DNA repair and transcription will be studied and, if warranted, a knock-in mouse model will be developed to establish the role of this modification in modulating tumorigenesis. Together, these studies will reveal how the E2F1 post-translational modification code is read by various chromatin-modifying activities to regulate both DNA repair and transcription. Determining how these E2F1 post-translational modifications impact the development of cancer will reveal new opportunities to modulate the activities of E2F1 to inhibit tumor growth and enhance the effectiveness of therapies.