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 病毒发病机理重要遗传决定因素。 录病毒 增强剂已经显示出影响白血病的发生、潜伏期 在某些情况下，细胞类型的特异性 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小鼠白血病病毒（Moloney）中的两个蛋白结合位点 MLV）增强子、白血病病毒因子B位点（LV B）和邻近的 “核心”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LVb位点结合Ets蛋白。 我们和其他人已经纯化了与相邻核心位点结合的蛋白质， 并分离编码几种核心结合因子的cDNA克隆 （CBF）. CBF由DNA结合α亚单位和β亚单位组成 与CBF α亚基结合，但本身不结合 DNA.在这里，我们建议继续表征生物化学 CBF α和β亚基的性质，并将这些 与病毒致病机制的关系。具体而言，我们计划： 1. 进行CBF亚单位的结构/功能分析。 2. 分析不同的序列特异性和结合亲和力， 用于莫洛尼病毒的CBF α和β亚基的组合 增强子及其对发病机制的贡献。 3. 分析Ets蛋白与CBF的相互作用。 4. 分析CBF β基因的生殖系突变对 T细胞发育和病毒发病机制。

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.