Control of Cellular Differentiation in Symbiotically Competent Cyanobacteria

共生蓝藻细胞分化的控制

• 批准号: 9514787
• 负责人: John Meeks
• 金额: $ 33万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9514787&HistoricalAwards=false
• 关键词: Control; Cellular; Differentiation; Symbiotically; Competent

*** 9514787 Meeks The long-term goal of this program is to identify, characterize and manipulate genes involved in cellular differentiation in the cyanobacterium Nostoc sp. strain ATCC 29133, a strain that can differentiate motile hormogonial filaments, akinetes (spores) and heterocysts, which are the sites of N2 fixation. Nostoc 29133 is also a facultative heterotroph that can establish a symbiotic association, via hormogonia, with the bryophyte Anthoceros punctatus. Anthoceros produces extracellular metabolites that sequentially stimulate hormogonia and heterocyst differentiation of Nostoc spp. to 10-fold or higher levels than those seen in its absence. The physiological and molecular genetic techniques developed in the prior grant and the transposon mutants currently in hand form the methodological and biological foundation of this proposal. Specific objectives are proposed in the following two areas. I . Heterocyst maturation is dependent on a signal cascade regulatory system. Analysis of Nostoc 29133: :Tn5-1063 strain UCD 311 (Fox~Sym+) with an insertion devR, encoding a receiver-domain-only response regulator protein. Biochemical and genetic assays to identify potential phosphodonors and phosphoreceivers of DevR. This project will identify members of a two component regulatory system involved in heterocyst development. 2. Hormogonia differentiation is a consequence of differential gene expression. Establishment and analysis of a hormogonia-specific subtractive cDNA library; generation by transposition of mutants of Nostoc 29133 altered in hormogonia formation; genetic characterization of such mutants and of cosmic clones from cDNA analysis. This project is the initial effort in understanding how cells divide uncoupled from DNA replication and biomass increase to form hormogonia and then return to the vegetative growth state in completing a cellular life cycle. ***

*** 9514787米克斯 该计划的长期目标是鉴定、表征和操纵蓝细菌Nostoc sp.菌株ATCC 29133中参与细胞分化的基因，该菌株可以分化能动的藻殖体丝、动丝（孢子）和异形胞，这些是N2固定的位点。念珠藻29133也是一种兼性异养生物，可以通过藻殖体与斑角蝇（Anthoceros punctatus）建立共生关系。Anthoceros产生胞外代谢产物，依次刺激念珠藻的藻殖子和异形胞分化。到10倍或更高的水平比那些在它的缺席。在先前的赠款和转座子突变体目前在手的生理和分子遗传技术开发形成的方法和生物学基础，这一建议。在以下两个领域提出了具体目标。I .异形胞成熟依赖于信号级联调节系统。具有插入devR的念珠藻29133：：Tn 5 -1063菌株UCD 311（Fox~Sym+）的分析，所述插入devR编码仅受体结构域的应答调节蛋白。生物化学和遗传测定，以确定潜在的磷酸供体和磷酸受体的DevR。这个项目将确定一个两个组件的调控系统的成员参与异形胞的发展。2.激素生殖器分化是基因表达差异的结果。藻殖体特异性消减cDNA文库的建立和分析;通过转座产生藻殖体形成改变的念珠藻29133突变体;从cDNA分析中对这些突变体和宇宙克隆进行遗传表征。该项目是了解细胞如何从DNA复制和生物量增加中分离出来，形成藻殖体，然后恢复到营养生长状态，完成细胞生命周期的初步努力。 ***