DIFFERENTIATION IN NITROGEN-FIXING BLUE-GREEN ALGAE

固氮蓝绿藻的分化

• 批准号: 2173805
• 负责人: ROBERT HASELKORN
• 金额: $ 21.16万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-05-01 至 1997-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2173805
• 关键词: Cyanophyta; DNA replication; Escherichia coli; cell differentiation; chromosomes; gel electrophoresis; gene expression; genetic manipulation; genetic mapping; genetic promoter element; genetic recombination; genetic transcription; messenger RNA; molecular cloning; mutant; nitrogen fixation; nucleic acid repetitive sequence; operon; peptidases; plant growth /development; plant proteins; protein biosynthesis

The goal of this program is an understanding of the factors that influence transcription during heterocyst differentiation in the cyanobacterium Anabaena. We have already purified and characterized the vegetative cell RNA polymerase and cloned most of the genes encoding its subunits, including the major sigma factor. We also have cloned genes for two additional sigma factors and for two proteins that regulate heterocyst differentiation. We will continue to define promoters specific for different cell types or for different stages of differentiation by deletion and point mutations, identify binding sites for transcription factors, construct suicide vectors for the selection of mutants unable to activate transcription of specific genes, design an expression system for Anabaena that allows control of transcript level in response to a small molecule, identify phosphorylated proteins that increase or decrease in response to environmental cues, and construct a high resolution physical map of the Anabaena chromosome. The map will permit the assignment of sets of genes with common regulation based on hybridization with a grid of cosmids that span the map. We are also interested in the origin and function of sets of short tandemly repeated sequences discovered at many locations in the chromosome, both following reading frames and, in one case, within the reading frame of an expressed and essential gene.

该计划的目的是了解因素 在杂环分化过程中影响转录 蓝细菌Anabaena。 我们已经纯化并表征了 营养细胞RNA聚合酶并克隆了大多数编码的基因 亚基，包括主要的Sigma因子。 我们也有克隆的基因 对于另外两个Sigma因子和两个调节的蛋白质 杂环分化。 我们将继续定义发起人 特定于不同的单元类型或不同阶段的 通过缺失和点突变分化，识别结合位点 对于转录因子，构建自杀向量进行选择 无法激活特定基因转录的突变体的设计 Anabaena的表达系统，可以控制转录级 响应一个小分子，鉴定磷酸化的蛋白质 响应环境线索并构建一个 Anabaena染色体的高分辨率物理图。 地图将 允许根据基于常见调节的基因分配 与跨越地图的宇宙网格的杂交。 我们也是 对一组短串联重复集的起源和功能感兴趣 在染色体的许多位置发现的序列，都以下 读取框架，在一种情况下，在表达的阅读框架内 和必需基因。