Role of EVI1 Modifications in Cell Transformation

描述：肿瘤转化是一个多步骤的过程，需要放松对控制祖细胞扩张和分化的关键细胞途径的调控。EVI1癌基因在许多组织中被不适当地激活，导致侵袭性实体癌和造血癌。EVI1在不同组织学组织转化中的作用机制尚不清楚。 3年前资助的这项提案的总体目标是确定EVI1如何赋予细胞逃脱包括分化和增殖在内的几种细胞途径的控制的能力，以及它如何促进细胞转化。这些研究表明，EVI1与主要调控蛋白相互作用，扰乱细胞周期、细胞增殖和正常分化。 在之前的资金周期中，我们还确定EVI1与几个转录辅调节因子和蛋白质修饰物相互作用，这些调节剂和蛋白质修饰物在翻译后通过可逆乙酰化或SUMO基化来修饰EVI1。更重要的是，通过使用点突变，我们已经确定了需要与这些修饰物的特定相互作用来改变EVI1对原代正常细胞的增殖和分化，并诱导永生化或转化。因此，我们认为EVI1干扰多条途径的能力是EVI1阳性癌症非常具有侵袭性的表型特征的基础。我们还提出，EVI1必须经过翻译后修饰，才能与关键的细胞调节因子相互作用，诱导细胞转化。我们确定在离散的核斑点中EVI1的组装需要EVI1修饰，我们认为这些斑点是EVI1活性的中心。因此，EVI1修饰的中断很可能会削弱EVI1改变其中至少一个途径的能力，导致肿瘤转化减弱或延迟。 这种相互竞争的更新有两个总体目标：识别和分析EVI1参与的多蛋白质复合体，以及确定需要哪些蛋白质修饰来改变增殖和分化。这项建议的具体目标是： 1.对EVI1的总甲基化和乙酰化进行研究，明确其在转录调控中的作用。 2.鉴定核EVI1多蛋白复合体的组成和功能。 3.研究EVI1在体内的总甲基化和乙酰化，并明确它们在EVI1诱导转化中的作用。

DESCRIPTION: Neoplastic transformation is a multistep process that requires the deregulation of key cellular pathways that control the expansion and the differentiation of progenitor cells. The EVI1 oncogene is inappropriately activated in many tissues resulting in aggressive solid and hematopoietic cancers. The mechanism by which EVI1 operates in the transformation of tissues of different histology is not clear. The overall goal of the proposal that was funded 3 years ago was to determine how EVI1 confers to the cell the ability to escape the control of several cellular pathways including differentiation and proliferation and how it contributes to cell transformation. These studies have shown that EVI1 interacts with master regulatory proteins to disrupt cell cycling, cell proliferation, and normal differentiation. During the prior funding cycle, we have also determined that EVI1 interacts with several transcription coregulators and protein modifiers, which post-translationally modify EVI1 by reversible acetylation or sumoylation. More importantly, by using point mutations we have established that specific interactions with these modifiers are required to alter proliferation and differentiation of primary normal cells by EVI1 and to induce immortalization or transformation. Therefore, we propose that the ability of EVI1 to disrupt multiple pathways is the basis of the very aggressive phenotype characteristic of EVI1-positive cancers. We also propose that EVI1 must be post-translationally modified in order to interact with key cell regulators and induce cell transformation. We determined that EVI1 modifications are required for the assembly of EVI1 in discrete nuclear speckles and we propose that these speckles are centers of EVI1 activity. Therefore, it is likely that disruption of EVI1 modification will impair the ability of EVI1 to alter at least one of these pathways, leading to attenuated or delayed neoplastic transformation. This competing renewal has two overall goals: to identify and analyze multi-protein complexes in which EVI1 participates and to determine which protein-modifications are required to alter proliferation and differentiation. The specific aims of the proposal are: 1. To characterize EVI1 sumoylation and acetylation and to define their role in transcription regulation. 2. To identify the components and the functions of the nuclear EVI1 multiprotein complexes. 3. To characterize the sumoylation and acetylation of EVI1 in vivo and to define their role in EVI1- induced transformation.