ETS TRANSCRIPTION FACTOR--THE PU.1-DNA COMPLEX

转录因子与特定的DNA序列结合， 重要的代谢功能，如细胞生长，发育和 分化人们对理解这一功能非常感兴趣 这些调节蛋白，特别是当它们的作用与 肿瘤发生PU.1转录因子是ets基因的成员 与红细胞白血病的发展有关的家族 和乳腺癌的肿瘤发生。ets蛋白质共有一个保守的 一个85个氨基酸的区域（ETS结构域），结合DNA并识别 富含嘌呤的序列，其核心序列为：5’-GGAA/T-3’。此域 代表一个新的，但未经表征的DNA结合基序，没有同源性， 其他DNA结合结构。PU.1结构域已结晶 与DNA复合，高分辨率X射线衍射数据已经 收集。在这个项目中，碘化DNA和重金属取代 蛋白质将被用来解决复杂的晶体相 通过多种同晶置换方法。将使用原子模型 了解ETS相关功能的分子基础， 转录因子，并评估其在发展中的作用， 癌将使用从DNA结合域获得的经验 表达和纯化全长PU.1蛋白用于结晶， 结构分析这种结构将揭示结构-功能 激活结构域与DNA结合结构域的关系。

Transcription factors bind to a specific DNA sequence and regulate important metabolic functions such as cell growth, development and differentiation. There is great interest in understanding the function of these regulatory proteins, especially when their role is linked to oncogenesis. The PU.1 transcription factor is a member of the ets gene family that have been implicated in the development of erythroid leukemia and tumorigenesis in breast cancers. The ets proteins share a conserved region of 85 amino acids (the ETS domain) that binds DNA and recognizes a purine-rich sequence with the core sequence: 5'-GGAA/T-3'. This domain represents a new, yet uncharacterized DNA-binding motif, with no homology to other DNA-binding structures. The PU.1 domain has been crystallized in complex with DNA and high resolution x-ray diffraction data have been collected. In this project, iodinated DNA and heavy metal-substituted protein will be used to solve the crystallographic phases of the complex by multiple isomorphous replacement methods. Atomic models will be used to understand the molecular basis for the function of ets-related transcription factors and to evaluate their role in the development of cancer. The experience gained from the DNA-binding domain will be used to express and purify full-length PU.1 protein for crystallization and structure analysis. This structure will reveal the structure-function relationship of the activation domain to the DNA-binding domain.