TRANSDUCTION OF THE A SIGNAL IN MYXOCOCCUS DEVELOPMENT

粘球菌发育中 A 信号的转导

• 批准号: 2415161
• 负责人: HEIDI B KAPLAN
• 金额: $ 22.21万
• 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 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2415161
• 关键词: DNA footprinting; Myxococcus; bacterial genetics; biological signal transduction; cell cell interaction; developmental genetics; gene expression; gene mutation; genetic mapping; genetic promoter element; genetic regulatory element; genetic transcription; genetic translation; microorganism growth; molecular cloning; northern blottings; nucleic acid sequence; nucleic acid structure; open reading frames; point mutation; posttranslational modifications; regulatory gene; site directed mutagenesis; starvation; transcription factor

Myxococcus xanthus represents an excellent model system to address fundamental questions of how cell-cell signaling pathways control multicellular development. These questions are relevant to all normal embryonic and adult cells which transduce signals to coordinate processes such as growth and differentiation, as well as to cells which are defective in signaling networks, such as cancer cells. Progression through early multicellular development requires that M. xanthus cells sense and respond to a high cell density and nutrient limitation. Two sensitive sensing networks which monitor these extracellular signals converge at a critical check point early in M. xanthus development. This check point can be monitored by expression of a specific gene, 4521; only if the conditions are correct for early M. xanthus development is this gene expressed. The long term goals of this research are to determine: i) How do the cells sense and transduce the cell-density signal? ii) How are the cell-density-and nutrient-sensing pathways integrated? iii) What is the connection between the change in gene expression and the complex behavioral response of multicellular fruiting body formation? To answer these questions our research focuses on identifying and characterizing the circuitry that connects the cell-density signal, extracellular A signal, to its responsive gene. The techniques of classical and molecular genetics, combined with protein biochemistry, will be used to characterize the A signal transduction pathway. We expect through this investigation to also gain insights into the mechanism by which M. xanthus integrates cell density and nutritional information. Specifically, we propose: i) to characterize the structure and function of sasB locus, a negative regulator of 4521 expression, thought to be a component of the A signaling pathway; ii) to identify and characterize the cis-acting elements controlling 4521 expression by mutational analysis; iii) to identify and characterize direct regulators of 4521 expression by purifying and characterizing proteins that bind to the 4521 upstream regulatory region. The genes encoding these proteins will be identified and characterized by DNA sequence analysis and mutagenesis; iv) to identify by genetic analysis additional components of the A signal pathway; and v) to characterize other early A signal-dependent developmental promoters by cloning, localizing, and sequencing these regions.

黄色粘球菌代表了一个优秀的模型系统来解决 细胞间信号通路如何控制的基本问题 多细胞发育。这些问题与所有正常人有关 胚胎和成体细胞转导信号以协调过程 例如生长和分化，以及细胞 信号网络有缺陷，例如癌细胞。 早期多细胞发育的进展需要 M. xanthus 细胞感知并响应高细胞密度和营养物质 局限性。两个敏感的传感网络监控这些 细胞外信号在 M 早期的关键检查点汇聚。 黄花的发育。该检查点可以通过以下表达式进行监控 特定基因，4521；仅当早期 M 的条件正确时。 黄花的发育就是这个基因的表达。本次活动的长期目标 研究的目的是确定： i) 细胞如何感知和转导 细胞密度信号？ ii) 细胞密度和营养感应如何 整合途径？ iii) 变化之间有何联系？ 基因表达和多细胞的复杂行为反应 子实体的形成？ 为了回答这些问题，我们的研究重点是识别和 表征连接细胞密度信号的电路， 细胞外A信号，对其反应基因。的技术 经典遗传学和分子遗传学，与蛋白质生物化学相结合，将 用于表征 A 信号转导途径。我们期望 通过这次调查也深入了解了这一机制 M. xanthus 整合了细胞密度和营养信息。 具体来说，我们建议：i）表征 sasB 基因座，4521 表达的负调节因子，被认为是 A信号通路的组成部分； ii) 识别并表征 通过突变分析控制4521表达的顺式作用元件； iii) 通过以下方式鉴定和表征4521表达的直接调节因子 纯化和表征与 4521 上游结合的蛋白质 监管区域。编码这些蛋白质的基因将被鉴定 并通过 DNA 序列分析和诱变进行表征； iv) 到 通过遗传分析识别 A 信号的其他成分 途径； v) 表征其他早期 A 信号依赖性 通过克隆、定位和测序这些发育启动子 地区。