STRUCTURE OF HEAT SHOCK TRANSCRIPTION FACTOR FROM YEAST

描述：拟议研究的主要目标是了解如何 蛋白质特异性识别DNA以及这种相互作用如何调节 转录调控 热休克转录因子（HSF）已被 选择研究，因为它的重要生物学作用和独特的 结构特征 HSF是真核转录激活因子， 热休克反应，一种进化上保守的机制， 细胞免受热量和其他环境干扰。 这种反应 也受到发育和生理刺激的激发。 HSF在 所有的真核生物，从酵母到人类。 酵母和果蝇只有一个 HSF，而更复杂的真核生物有多个HSF， 不同的压力和表现出差异基因表达。 HSF是一个 只有几个序列特异性同源三聚体DNA结合的例子， 蛋白质，和HSF的时间性质提出了有趣的问题，如何 一个三重对称的蛋白质可以与DNA结合。 除了绑定为 HSF是一种三聚体，它与DNA具有多层协同作用 结合，这种协同性对启动子的功能有影响。 体内选择性。 所有的HSF识别相同的DNA序列，称为 热冲击元件（HSE），并具有一个共同的，保存的核心，包括 DNA结合和三聚化结构域。 仅含有HSF的片段 该核具有与完整核相同的DNA结合和寡聚化性质， 长度HSF。 这些碎片非常适合物理研究， 酵母HSF适用于遗传方法。 由于保护 酵母HSF的研究直接适用于人HSF。 所提出的方法的关键是生物化学， 晶体学和遗传学研究。 本提案的具体目标 了解HSF对DNA结合位点特异性的基础 通过关注DNA结合结构域-HSE相互作用;表征 两个不寻常的结构特征的作用， DNA结合结构域和被假定参与协同性; 并确定一个三重对称的， 三聚体蛋白质必须结合DNA。 这些实验将加深我们的 了解HSF如何与HSEe结合，并最终导致长期的 长期目标是能够操纵HSF的功能，以便采取 发挥其保护作用。

DESCRIPTION: The major goal of the proposed research is to understand how proteins specifically recognize DNA and how this interaction modulates transcriptional regulation. Heat shock transcription factor (HSF) has been chosen for study because of its important biological role and unique structura features. HSF is the eukaryotic transcriptional activator for the heat shock response, an evolutionarily conserved mechanism which protects cells from heat and other environmental perturbations. This response is also invoked by developmental and physiological stimuli. HSF is found in all eukaryotes, from yeast to humans. Yeast and fruitflies have a single HSF, while more complex eukaryotes have multiple HSFs, which respond to different stresses and exhibit differential gene expression. HSF is one of only a few examples of a sequence-specific, homotrimeric DNA binding protein, and the timeric nature of HSF poses interesting questions about how a three-fold symmetric protein can bind to DNA. In addition to binding as a trimer, HSF has multiple layers of cooperativity involved with it DNA binding, and this cooperativity has functional implications for promoter selectivity in vivo. All HSFs recognize the same DNA sequence, called a heat shock element (HSE), and have a common, conserved core that includes the DNA binding and trimerization domains. Fragments of HSF containing just this core have the same DNA Binding and oligomerization properties as full length HSF. These fragments are highly amenable to physical studies, and yeast HSF is amenable to genetic approaches. Because of the conservation of HSFs, studies o yeast HSF are directly applicable to human HSFs. The key to the proposed approach is the interplay between biochemical, crystallographic, and genetic studies. The specific aims of this proposal are to: understand the basis of HSF's specificity to its DNA binding site by focusing on the DNA binding domain-HSE interaction; characterize the functiona role of two unusual structural features that are located within the DNA bindin domain and are postulated to be involved in cooperativity; and determine the structural accommodations that a three-fold symmetric, trimeric protein must make to bind DNA. These experiments will deepen our understanding of how HSF binds to HSEe and will eventually lead to the long term goal of being able to manipulate HSF's function in order to take advantage of its protective role.