Genetics of Heterocyst Differentiation and Patterning

异形囊分化和模式的遗传学

• 批准号: 0343998
• 负责人: Sean Callahan
• 金额: --
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0343998&HistoricalAwards=false
• 关键词: Genetics; Heterocyst; Differentiation; Patterning

The development of a pattern of differentiated cell types from a group of equivalent cells is a fundamental paradigm in biology. In bacteria, the differentiation of nitrogen-fixing heterocysts from a filament of vegetative cells by some cyanobacteria represents one of the few examples of a developmental pattern that can be maintained indefinitely given the appropriate environmental conditions. It represents a simple model system for elucidation of the minimal set of genetic elements that are necessary for pattern generation and maintenance by an organism. Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can be induced to differentiate a pattern of nitrogen-fixing heterocysts from a chain of undifferentiated vegetative cells. Heterocysts occur, on average, at 10 cell intervals, are terminally differentiated, and differ from vegetative cells morphologically, metabolically, and genetically. The first objective of the project is the identification and characterization of genetic elements that are involved in development. A mutagenic approach will be pursued using a genetically engineered strain of Anabaena 7120 that can be induced to form close to 100% heterocysts under conditions that do not require differentiation for growth. The second objective of the project is to test two hypotheses that relate to inhibition of differentiation by the gene hetN. The third objective is the identification and characterization of additional genes that are necessary for inhibition of differentiation by hetN. This project is narrowly focused on the genetics of heterocyst differentiation in cyanobacteria, but the broader biological impact will be on differentiation and pattern formation in general.

从一组等效细胞中分化细胞类型的模式的发展是生物学的基本范式。 在细菌中，某些蓝细菌与植物细胞的细胞的固定杂环的分化代表了鉴于适当的环境条件，可以无限期地维持发育模式的少数例子之一。 它代表了一个简单的模型系统，用于阐明生物体模式产生和维护所需的最小遗传元素集。 Anabaena sp。 PCC 7120菌株是一种丝状蓝细菌，可诱导以区分氮固定杂环与未分化的营养细胞链。 杂环平均以10个细胞间隔发生终端分化，并且在形态，代谢和遗传上与营养细胞不同。 该项目的第一个目的是鉴定和表征发展中涉及的遗传因素。 在不需要分化生长的条件下，可以使用Anabaena 7120的基因工程菌株进行诱变方法，该菌株可引起接近100％的杂环。 该项目的第二个目标是检验两个与基因抑制分化有关的假设。 第三个目标是鉴定和表征其他基因，这些基因是抑制HETN分化所必需的。 该项目狭义地集中在蓝细菌中杂细胞分化的遗传学上，但是更广泛的生物学影响将对分化和模式形成。