E2F7 & E2F8 in the control of transcription and cellular proliferation

转录因子E2F家族被认为在控制细胞内 扩散。这些因子由不同的基因编码，既有肿瘤抑制作用，又有致癌作用。 功能(1-2)。我们实验室确认E2F7和E2F8是该转录因子的最后两个成员 家庭(5，6)。本提案中提供的初步数据突出了这两个项目的几个独特之处 E2F将它们放在自己的子类中。这些显著特征包括它们形成的能力 同源二聚体和异源二聚体，与一大批转录共抑制因子相关联，以沉默 基因表达，并阻断细胞增殖。虽然它们缺乏典型的RB结合结构域，但E2F7可以 特异性地与RB相关蛋白相互作用，从而可以将E2F8招募到含有RB的复合体中。作为一名 结果：E2F网络中的E2F7/8臂仍受细胞周期依赖性激酶(CDK)的控制 信号通路。E2F7和E2F8具有相同的细胞周期依赖模式和组织- 特定的表达，加上它们同源和异源二聚体的能力，增加了它们 可能在动物身上既有独特的功能，又有共同的功能。实验室的多方面努力取得了成果 关键技术发展，包括纯化E2F7/8相关蛋白的亲和纯化策略， 启动子阵列技术用于识别靶基因，基因打靶方法用于干扰E2F7和 小鼠的E2F8。这些进展使我们的研究小组处于有利地位，能够取得重大进展 对E2F家族的这一重要分支是如何控制细胞的机械性理解 细胞周期和细胞增殖。这一提议的首要假设是E2F7和E2F8的功能是 转录抑制因子，以负向控制细胞增殖。利用生化的三个具体目标， 生物物理学、全球基因阵列和遗传学方法将直接检验这一假设：具体目标1。 鉴定和鉴定E2F7和E2F8相关的大分子蛋白质复合体。具体目标2. 鉴定E2F7和E2F8转录靶点。明确E2F7和E2F7的发病机制 E2F8在转录调控中的作用。这项工作将阐明个体和组合 这两位高度相关的家庭成员对全面了解E2F的贡献 转录活性。 项目说明第6页

The E2F family of transcription factors is believed to play a critical role in the control of cellular proliferation. These factors are encoded by distinct genes and have both tumor suppressor and oncogenic functions (1-2). Our laboratory identified E2F7 and E2F8 as the final two members of this transcription factor family (5, 6). The preliminary data presented in this proposal highlight several unique features of these two E2Fs that place them in a subclass of their own. These salient features include their ability to form homodimers and heterodimers, to associate with a large cadre of transcriptional co-repressors, to silence gene expression, and to block cellular proliferation. While they lack a typical Rb-binding domain, E2F7 can specifically interact with Rb related proteins and can thus recruit E2F8 to Rb-containing complexes. As a result, the E2F7/8 arm of the E2F network remains under the control of the cycling dependent kinase (CDK) signaling pathway. The fact that E2F7 and E2F8 have an identical pattern of cell cycle dependent and tissue- specific expression, together with their ability to homo- and hetero-dimerize, raises the possibility that they may have both unique and shared functions in the animal. A multi-faceted effort in the laboratory has yielded key technical developments, including an affinity purification strategy to purify E2F7/8-associated proteins, promoter-array technologies to identify target genes, and gene targeting approaches to disrupt E2F7 and E2F8 in mice. These advances place our research group in a strong position to make significant advances towards a mechanistic understanding of how this important arm of the E2F family of factors controls the cell cycle and cell proliferation. The overarching hypothesis of this proposal is that E2F7 and E2F8 function as transcriptional repressors to negatively control cellular proliferation. Three specific aims utilizing biochemical, biophysical, global gene array, and genetic approaches will directly test this hypothesis: Specific Aim 1. To identify and characterize E2F7- and E2F8-associated macromolecular protein complexes. Specific Aim 2. To identify E2F7 and E2F8 transcriptional targets. Specific Aim 3. To determine the mechanism of E2F7 and E2F8 action in the control of transcription. This work will elucida the individual and combinatorial contributions made by these two highly related family members towards the overall understanding of E2F transcriptional activity. Project Description Page 6