TRANSDUCTION OF THE A SIGNAL IN MYXOCOCCUS DEVELOPMENT

粘球菌发育中 A 信号的转导

• 批准号: 2184876
• 负责人: HEIDI B KAPLAN
• 金额: $ 18.07万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-01 至 1996-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2184876
• 关键词: DNA footprinting; Myxococcus; bacterial genetics; biological signal transduction; cell cell interaction; developmental genetics; gene expression; gene mutation; genetic mapping; genetic regulatory element; genetic translation; microorganism growth; northern blottings; nucleic acid sequence; open reading frames; point mutation; regulatory gene; starvation

Myxococcus xanthus uses cell-cell interactions to coordinate a developmental program in which cells aggregate to form organized multicellular fruiting bodies and differentiate from rod-shaped cells into ovoid spores. This developmental program is initiated by nutrient limitation at a high cell density. After the removal of nutrients, M. xanthus cells sense their nutritional status and cell density by monitoring the increase in the extracellular A signal concentration, and subsequently activate the A signal transduction pathway. Activation occurs only when the extracellular A signal concentration is within a specific intermediate range. Using a sensitive sensing mechanism, the A signal pathway directs the progression through the early stages of M. xanthus development. Our long term goals are to determine: 1) how the cells sense the extracellular A signal concentration, 2) how this information is transduced, resulting in a change in gene expression and 3) what is the connection between the change in gene expression and the complex behavioral response of multicellular fruiting body formation. To answer these questions we will characterize the regulatory network of the A signal transduction pathway. Several components of this circuitry have been identified, including the extracellular signal, A signal, and a specific response, an increase in expression of a gene, gene4521. A regulatory element has been identified which maps to the sasA (for suppressor of A signal) locus. The sasA locus is required for the progression through early development and differentially regulates the expression of distinct A signal-dependent genes. The focus of this research is to use classical and molecular genetic techniques, combined with protein biochemistry, to fully characterize the sasA locus and its encoded regulatory element. Molecular genetic approaches will be used to analyze the sasA locus structure by defining the physical limits of the locus, analyzing the transcripts, sequencing the region, identifying the open reading frame(s), and construction and characterizing a null mutation. To study the function of the sasA gene product we will determine if the sasA gene product directly or indirectly regulates gene4521 expression. First, the cis-acting regulatory elements controlling gene4521 expression will be determined by deletion analysis. Then, biochemical techniques will be used to test binding of purified sasA gene product to the gene4521 regulatory region. Any binding activity will be characterized in detail. If the sasA gene product appears to indirectly regulate gene4521 expression, biochemical techniques as well as genetic screens will be used to identify possible intermediate regulatory elements. In addition, genetic screens will be developed to identify other components of the A signal transduction pathway, which will likely include a receptor and additional transduction elements.

xanthus粘菌OSCOCCOCCOCCOCCOCCOCCOCCOCCUS使用细胞 - 细胞相互作用来坐标 开发程序，其中细胞聚集形成有组织的 多细胞水果体，与棒状细胞区分开 进入卵形孢子。 该开发计划是由营养素启动的 高细胞密度的限制。 去除营养后，M。 叶thus细胞通过 监测细胞外A信号浓度的增加，并 随后激活A信号转导途径。 激活 仅当细胞外A信号浓度在A内时发生 特定的中间范围。 使用敏感的感应机制， 信号途径指导了M.的早期阶段的进展。 Xanthus开发。 我们的长期目标是确定：1​​）细胞如何感知 细胞外A信号浓度，2）此信息如何 转导，导致基因表达变化，3）什么是 基因表达变化与复合物之间的联系 多细胞果实身体形成的行为反应。 回答 这些问题我们将表征A的监管网络 信号转导途径。 该电路的几个组件具有 已被鉴定出，包括细胞外信号，一个信号和A 具体反应，基因表达的增加，基因4521。 一个 已经确定了调节元素的映射到SASA（用于 信号的抑制器）基因座。 SASA基因座是需要的 通过早期发展的进展，并差异地调节 不同信号依赖性基因的表达。 这项研究的重点是使用经典和分子遗传 与蛋白质生物化学相结合的技术，以完全表征 SASA基因座及其编码的调节元件。 分子遗传 方法将通过定义来分析SASA基因座结构 基因座的物理极限，分析转录本，测序 该地区识别开放阅读框架和构造和 表征无效突变。 研究SASA基因的功能 产品我们将确定SASA基因产品是否直接或 间接调节基因4521表达。 首先，顺式作用 将确定控制基因4521表达的调节元素 通过删除分析。 然后，生化技术将用于测试 纯化的SASA基因产物与基因4521调节区域的结合。 任何结合活动都将详细表征。 如果SASA基因 产品似乎间接调节基因4521表达，生化 技术和遗传筛选将用于识别可能 中间监管元素。 此外，遗传筛查将是 开发以识别A信号转导的其他组件 途径，它可能包括一个受体和额外 转导元素。