REGULATION OF GENE EXPRESSION

基因表达的调控

• 批准号: 3874634
• 负责人: J BRADY
• 金额: --
• 依托单位: DIVISION OF CANCER EPIDEMIOLOGY AND GENETICS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3874634
• 关键词: DNA; DNA binding protein; affinity chromatography; aminoacid; binding proteins; gel electrophoresis; gene expression; gene interaction; genetic promoter element; genetic transcription; genetically modified animals; human T cell leukemia; human T cell lymphotropic virus type 1; human immunodeficiency virus; laboratory mouse; neoplasm /cancer genetics; oncoproteins; open reading frames; protein purification; tissue /cell culture; transcription factor; viral carcinogenesis; virus genetics; zinc

The human T-cell leukemia virus, HTLV-I, has been established as the etiological agent for adult T-cell leukemia. The 3' long open reading frame of the human T-cell leukemia virus type-I (HTLV-I) encodes a 40 kD protein (Tax1). This protein positively regulates transcription directed by the HTLV-I long terminal repeat (LTR). We have been unable to attribute any sequence-specific DNA binding properties to Tax1, suggesting that the protein activates the HTLV-I promoter in an indirect fashion using cellular transcription factors. Our objective is to understand the biochemical mechanism of transactivation by the Tax1 protein and the involvement of cellular transcription factors in this process. We have identified two distinct Taxi-responsive elements (TRE-1 and TRE-2) in the viral LTR. A 36 kD protein identified in HeLa nuclear extract mediates the interaction of Tax1 with TRE-2. Purification of this protein was achieved by zinc chelate chromatography and preparative SDS-polyacrylamide gel electrophoresis. The renatured 36 kD protein bound specifically to a TRE-2 oligonucleotide, but not to nonfunctional base substitution mutant probes in a gel retardation assay. The 36 kD protein specifically activated transcription from the HTLV-I promoter in vitro. Extracellular HTLV Tax1 is taken up by lymphoid tissue culture cells. Approximately 80% of the protein is localized to the nucleus. Two biological properties of the uptake have been analyzed. First, in 7OZ/3 pre-B cells, the NFkB transcription factor is activated. Second, in peripheral blood lymphocytes, Tax1 acts to stimulate progression of PHA stimulated cells to the cell division cycle.

人类 T 细胞白血病病毒 HTLV-I 已被确定为 成人 T 细胞白血病的病原体。 3'长开放阅读框 人类 T 细胞白血病病毒 I 型 (HTLV-I) 编码 40 kD 蛋白质 （税1）。该蛋白正向调节由 HTLV-I 长末端重复序列 (LTR)。我们无法归因于任何 与 Tax1 的序列特异性 DNA 结合特性，表明 蛋白质利用细胞间接方式激活 HTLV-I 启动子 转录因子。我们的目标是了解生化 Tax1 蛋白的反式激活机制及其参与 这一过程中的细胞转录因子。我们已经确定了两个 病毒 LTR 中存在不同的 Taxi 响应元件（TRE-1 和 TRE-2）。 36 HeLa 核提取物中鉴定出的 kD 蛋白介导以下相互作用： Tax1 与 TRE-2。通过锌螯合物纯化该蛋白质 色谱法和制备型 SDS-聚丙烯酰胺凝胶电泳。这 复性的 36 kD 蛋白质特异性结合 TRE-2 寡核苷酸，但是 不用于凝胶延迟中的非功能性碱基取代突变体探针 化验。 36 kD 蛋白特异性激活转录 体外HTLV-I启动子。 细胞外 HTLV Tax1 被淋巴组织培养细胞吸收。 大约80%的蛋白质定位于细胞核。二 对摄取的生物学特性进行了分析。一、7OZ/3 前 B 细胞中，NFkB 转录因子被激活。其次，在 外周血淋巴细胞，Tax1 可以刺激 PHA 的进展 刺激细胞进入细胞分裂周期。