TRANSDUCTION OF THE A SIGNAL IN MYXOCOCCUS DEVELOPMENT

粘球菌发育中 A 信号的转导

• 批准号: 2701558
• 负责人: HEIDI B KAPLAN
• 金额: $ 24.48万
• 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/2701558
• 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; 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.

粘粒Xanthus代表了一个出色的模型系统来解决 细胞电池信号通路如何控制的基本问题 多细胞发展。这些问题与所有正常 胚胎和成人细胞，这些细胞将信号转换为协调过程 例如生长和分化，以及细胞 信号网络（例如癌细胞）中有缺陷。 通过早期多细胞发展的进展要求M. 叶thus细胞感知并响应高细胞密度和养分 局限性。两个敏感的传感网络，可以监视这些 细胞外信号在M早期在临界检查点收敛。 Xanthus开发。可以通过表达来监视此检查点 特定基因，4521；只有在适合早期的条件正确的情况下。 Xanthus发育是该基因表达的。这个长期目标 研究是确定：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 途径集成？ iii）更改之间的联系是什么 基因表达和多细胞的复杂行为反应 果实的身体形成？ 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，其反应性基因。这些技术 经典和分子遗传学，结合蛋白质生物化学，将 用于表征A信号转导途径。我们期望 通过这项调查，还可以深入了解该机制 Xanthus整合细胞密度和营养信息。 具体来说，我们建议：i）表征 SASB基因座是4521表达的负调节剂，被认为是一个 A信号通路的组成部分； ii）识别和表征 通过突变分析控制4521表达的顺式作用元件； iii）通过 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 并以DNA序列分析和诱变为特征； iv） 通过遗传分析识别A信号的其他组件 途径； v）表征其他早期信号依赖性的 通过克隆，本地化和测序来开发启动子 地区。