ACTIVATING TRANSCRIPTION FACTOR 2 PROTEIN INTERACTIONS

激活转录因子-2(ATF-2)是CREB(环状 AMP反应元件结合蛋白)/ATF转录因子家族。 虽然它普遍存在于哺乳动物组织中，但ATF-2的作用 在正常情况下，细胞功能尚不清楚。实验表明，ATF-2 具有与细胞周期相关的作用：a)ATF-2在 G1和G2/M期细胞，以及b)类似的ATF-2核转位是 对促有丝分裂生长因子刺激的反应，包括 表皮生长因子。尽管它已经被证明可以调解- 内源性腺病毒E1a蛋白的转录激活 ATF-2功能的细胞调节因子尚未确定。腺病毒 Ela蛋白不直接与DNA结合；它能够激活基因 通过与DNA结合的ATF-2相互作用进行转录。我们假设ATF- 2以类似的方式与内源性细胞蛋白相互作用，形成 调控细胞周期依赖基因的转录复合体 表情。本提案中描述的实验的目标是 与ATF-2相互作用形成的哺乳动物蛋白的鉴定 转录复合体，将积极或消极的信号传导到 RNA聚合酶，以影响特定基因的表达。这将是 通过筛选小鼠胚胎表达的蛋白质来完成的 文库，在酵母双杂交系统中与ATF-2相互作用。 与ATF-2相互作用的蛋白质将被表达、纯化和 已排序。组织特异性、DNA结合能力和 这些蛋白质的转录激活潜力将是 特色化的。CREB/ATF转录因子家族在 细胞信号转导和在细胞生长和调节中的作用 差异化。基于结构/功能的实验 CREB和ATF-2的特点将对指导 未来的癌症治疗方案。描述蛋白质的作用-- 转录激活中的蛋白质相互作用是重要的 理解正常和异常的机制 调控基因表达、细胞生长、细胞分化和 致癌作用。

Activating transcription factor-2 (ATF-2) is a member of the CREB (cyclic AMP response element binding protein)/ATF family of transcription factors. Though it is present ubiquitously in mammalian tissues, the role of ATF-2 in normal cellular function is not known. Experiments suggest that ATF-2 has a cell cycle-related role: a) ATF-2 is translocated to the nucleus in Gl and G2/M phase cells, and b) similar nuclear translocation of ATF-2 is seen in response to stimulation with mitogenic growth factors, including epidermal growth factor. Though it has been shown to mediate - transcriptional activation by adenoviral E1a protein, an endogenous cellular regulator of ATF-2 function has not been identified. Adenoviral Ela protein does not directly bind DNA; it is able to activate gene transcription by interacting with DNA-bound ATF-2. We postulate that ATF- 2 interacts with endogenous cellular proteins in a similar fashion to form transcriptional complexes which regulate cell cycle-dependent gene expression. The goal of the experiments described in this proposal is the identification of mammalian proteins that interact with ATF-2 to form transcriptional complexes which transduce positive or negative signals to RNA-polymerase to effect expression of specific genes. This will be accomplished by screening for proteins, expressed by a mouse embryo cDNA library, which interact with ATF-2 in the yeast two-hybrid system. Proteins which interact with ATF-2 will be expressed, purified and sequenced. The tissue specificities, DNA-binding capabilities and transcriptional activation potential of these proteins will be characterized. The CREB/ATF family of transcription factors function in cellular signal transduction and in the regulation of cell growth and differentiation. Experiments based on the structure/function characteristics of CREB and ATF-2 will have implications for guiding future protocols of cancer therapy. Delineation of the role of protein- protein interactions in transcriptional activation is important for understanding the mechanisms involved in the normal and abnormal regulation of gene expression, cell growth, cell differentiation and oncogenesis.