BIOCHEMISTRY OF LEUKEMIA VIRUS CORE-BINDING FACTOR

C型致癌逆转录病毒的转录增强子是一种 病毒致病的重要遗传决定因素。逆转录病毒 增强剂已被证明会影响白血病的致瘤性，潜伏期 疾病的发病，在某些情况下，细胞类型特异性 白血病。我们的长期目标是了解 转录增强子赋予这些致病表型。 Moloney鼠白血病病毒(Moloney)中的两个蛋白结合位点 MLV)增强子、白血病病毒B因子B位点(LVB)及其邻近的 ‘core’序列是胸腺疾病的主要遗传决定因素 莫洛尼病毒的特异性。直播站点绑定了ETS蛋白。 我们和其他人已经提纯了与邻近核心部位结合的蛋白质， 和编码几个核心结合因子的分离的cDNA克隆 (CBF)。CBF由DNA结合的α亚基和β亚基组成 它与CBFα亚单位相关联，但本身并不结合 DNA在这里，我们建议继续描述生物化学 CBFα和β亚基的性质，并将它们相互关联 与病毒致病机制有关的特性。具体来说，我们计划： 1.进行CBF亚基的结构/功能分析。 2.分析不同基因的序列特异性和结合亲和力。 Moloney病毒CBFα和β亚基的组合 增强子及其在发病机制中的作用。 3.分析ETS蛋白与CBF的相互作用。 4.分析CBFβ基因的胚系突变对 T细胞发育与病毒致病机制。

The transcriptional enhancer of C-type oncogenic retroviruses is an important genetic determinant of viral pathogenesis. Retroviral enhancers have been shown to influence leukemogenicity, the latent period of disease onset, and in some cases the cell type specificity of leukemia. Our long-term objective is to understand how the transcriptional enhancer confers these pathogenic phenotypes. Two protein binding sites in the Moloney murine leukemia virus (Moloney MLV) enhancer, the Leukemia virus factor b site (LVb) and the adjacent 'core' sequence, are major genetic determinants of the thymic disease specificity of the Moloney virus. The LVb site binds the Ets proteins. We and others have purified proteins that bind to the adjacent core site, and isolated cDNA clones encoding several of the core-binding factors (CBF). CBF consists of a DNA binding alpha subunit, and a beta subunit that associates with a CBF alpha subunit, but does not by itself bind DNA. Here we propose to continue characterizing the biochemical properties of the CBF alpha and beta subunits, and correlate these properties with viral pathogenesis. Specifically, we plan to: 1. Perform structure/function analyses of the CBF subunits. 2. Analyze the sequence specificity and binding affinity of various combinations of CBF alpha and beta subunits for the Moloney virus enhancer, and their contribution to pathogenesis. 3. Analyze the interaction between the Ets proteins and CBF. 4. Analyze the effects of a germline mutation in the CBF beta gene on T cell development and viral pathogenesis.