Molecular Mechanisms of eIF4E mediated transformation

摘要 这项修订后的续签申请调查了驱动后监管失调的新机制。 癌症中的转录调控。事实上，这些事件的失调可能会推动产量 支持增殖、存活、侵袭和转移的蛋白质。监管失调可能 发生在RNA加工的多个层面，包括RNA的剪接、它们的核输出和 翻译。真核细胞翻译起始因子eIF4E在约30%的肿瘤中表达异常 包括在急性髓系白血病(AML)中，控制着网络的RNA处理 最终支持其致癌活性的转录本。它管理这些规则的能力 被归因于其在核出口和具体的翻译方面的既定角色 RNA。在这里，我们发现eIF4E重新编程了数千个 转录本在急性髓系白血病患者中作为eIF4E异常的功能以及eIF4E的功能 在模型系统中过度表达。我们比较了高eIF4E中的选择性剪接(AS)事件 AML和eIF4E在细胞中过表达时，假设这些共同之处将代表 依赖eIF4E的剪接的泛癌靶点。我们发现了一组~150作为“核心” 转录本，在相同的生化网络中编码因子。重要的是，这些 通路在急性髓系白血病和更广泛的癌症中也起着作用。许多AS活动都是 预测会产生具有不同结构域结构的蛋白质，从而改变功能。 至于eIF4E调节AS的机制，我们的研究发现了 EIF4E与剪接体各组分的相互作用及新发现 控制拼接机械生产的手段，即通过eIF4E。三个目标是 建议剖析与这些小说相关的机械原理和生物影响 发现：目的1.探索依赖eIF4E的剪接改变，我们将在其中解剖 EIF4E的生化活性是其AS活性所需的，并评估 这项活动；目的2.阐明eIF4E在重新编程剪接中所起的生化作用 通过解剖eIF4E与剪接体组件和 确定其与活性剪接体的关系；以及目标3.确定 AML中不受调控的eIF4E依赖的剪接，我们将探索AS，和 确定eIF4E活动所需的剪接因子。这些研究将改变我们的观点 关于eIF4E失调的影响，现在将包括改变 转录本以及调节其蛋白质编码能力。

Abstract This revised renewal application investigates novel mechanisms driving dysregulation of post- transcriptional control in cancer. Indeed, dysregulation of these events can drive the production of proteins that underpin proliferation, survival, invasion and metastases. Dysregulation can occur at many levels of RNA processing including splicing of RNAs, their nuclear export and translation. The eukaryotic translation initiation factor eIF4E, dysregulated in ~30% of cancers including in acute myeloid leukemia (AML), governs the RNA processing of networks of transcripts that ultimately underpin its oncogenic activities. Its ability to govern these regulons has been attributed to its well-established roles in nuclear export and translation of specific RNAs. Here, we discovered that eIF4E reprograms the splicing landscape of 1000s of transcripts both as a function of eIF4E dysregulation in AML patients as well as upon eIF4E overexpression in model systems. We compared alternative splicing (AS) events in high-eIF4E AML and upon eIF4E overexpression in cells, postulating those in common would represent pan-cancer targets of eIF4E-dependent splicing. We discovered a set of ~150 AS “core” transcripts, which encoded factors in the same biochemical networks. Importantly, these pathways also play roles in AML and in cancer more generally. Many of the AS events are predicted to produce proteins with different domain structures and thus altered functionalities. As to the mechanisms by which eIF4E modulates AS, our studies unearthed physical interactions between eIF4E and components of the spliceosome as well as revealed novel means to control the production of the splicing machinery i.e. via eIF4E. Three aims are proposed to dissect the mechanistic principles and biological impacts related to these novel findings: Aim 1. Explore eIF4E-dependent alterations to splicing where we will dissect the biochemical activities of eIF4E required for its AS activity, and assess the functional outcome of this activity; Aim 2. Elucidate the biochemical role that eIF4E plays in re-programming splicing by dissecting the physical interactions of eIF4E with components of the spliceosome and ascertain its relationship with active spliceosomes; and Aim 3. Determine the impact of dysregulated eIF4E-dependent splicing in AML where we will explore the impact of AS, and identify the splicing factors required for eIF4E’s activity. These studies will transform our view with regard to the impact of eIF4E dysregulation, which would now include altering the form of the transcript as well as regulating its protein-coding capacity.