The E2F1 Post-Translational Modification Code

项目总结 在大多数癌症中，E2F1转录因子通过破坏p16INK4A-细胞周期蛋白D-RB而被解除调控 肿瘤抑制途径但E2F1在癌症中的作用是复杂的，因为它既可以促进，也可以抑制 肿瘤的发展取决于具体情况。E2F1也可以在分子水平上具有相反的活性，通过 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， E2F1可以直接刺激DNA修复，而不依赖于它在转录中的作用。这些项目的长期目标是 研究是为了了解E2F1的各种功能是如何在细胞中调节的，以及每个功能是如何 活动有助于癌症的发展或抑制。E2F1被磷酸化，乙酰化， 和甲基化以响应DNA损伤，但这些修饰如何改变E2F1的活性仍然存在 人们对此知之甚少。这一建议是基于这样一种假设，即翻译后的修改 E2F1由相互作用的蛋白质读取，以调节E2F1在DNA修复中的定位和功能， 转录与肿瘤发生。TopBP1蛋白被磷酸化后与E2F1特异性结合 这种相互作用导致E2F1向DNA损伤部位募集。目标1 研究将使用一种新型的敲入小鼠模型(S29A)来确定E2F1的磷酸化 E2F1及其相关蛋白在动态改变DNA位点染色质结构中的作用 损坏，便于维修。初步数据表明，E2F1乙酰化创建了一个结合基序 CBP和p300乙酰转移酶的溴区。一种新型的阻断E2F1基因敲入小鼠模型 乙酰化将用于研究E2F1-CBP/p300相互作用如何调节组蛋白乙酰化和 修饰DNA损伤部位的染色质结构以促进修复。这些敲入的老鼠也将被使用 研究E2F1乙酰化在调节转录和抑制肿瘤发展中的作用(目标2)。 TDRD3蛋白被鉴定为E2F1精氨酸甲基化标记(R109me)的潜在阅读器。这个 将研究TDRD3在调节依赖于E2F1的功能中对DNA修复和转录的作用，如果 在保证的情况下，将开发一个敲入小鼠模型来确定这种修饰在调节中的作用 肿瘤发生学。总之，这些研究将揭示E2F1翻译后修饰代码是如何被 各种染色质修饰活动来调节DNA修复和转录。确定这些功能如何 E2F1翻译后修饰影响癌症发展将揭示新的机会 调节E2F1的活性，抑制肿瘤生长，提高治疗效果。

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.