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TRANSCRIPTIONALLY REGULATED GENES IN A SYMBIOSIS

共生中的转录调控基因

基本信息

批准号：
3291963
负责人：
SANDRA A NIERZWICKI-BAUER
金额：
$ 16.93万
依托单位：
RENSSELAER POLYTECHNIC INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
1986
资助国家：
美国
起止时间：
1986-07-01 至 1989-12-31
项目状态：
已结题

项目摘要

The major goal of the proposed research is to provide a more complete understanding, at the molecular level, of interactions between the eukaryotic water fern Azolla and its endosymbiont, the filamentous cyanobacterium Anabaena. Molecular and ultrastructural techniques will be used to achieve this goal. Two genes that are transcriptionally regulated when Anabaena is in the symbiotic state will be characterized in greater detail in the proposed work. These are the g1nA and psbA genes, which encode glutamine synthetase and the 32-kD protein of photosystem II. We plan to determine the structure and analyze the expression of these genes in the endosymbiont. The g1nA gene will be identified and isolated from a genomic library of endosymbiont DNA. The 5'-flanking and amino-terminal regions of this gene will be identified and sequenced. The g1nA promoter(s) used by the endosymbiont for transcription will be identified. Glutamine synthetase will be localized within individual cells of cyanobacterial filaments with immunoelectron microscopy. With respect to the psbA genes, the number of genes comprising this multi-gene family will be determined. All members of this gene family will be isolated from a genomic library. Unique DNA fragments that can serve as gene-specific probes for the different members of the psbA gene family will be identified. Specific gene copies that are transcribed in the endosymbiont will be identified. Also, it will be determined whether different sized psbA transcripts found in endosymbiont RNA are the result of specific processing, transcription of different gene copies, or both. It will be determined whether psbA genes are transcribed in heterocysts. Also, the location of 32-kD proteins within cells of cyanobacterial filaments will be elucidated with immunoelectron microscopy. This work will provide answers to basic questions regarding the heterocyst differentiation process of cyanobacteria,k and indeed the mechanism of cellular differentiation in the broadest sense: where are GS and the 32-kD proteins located, and how are their genes regulated. The proposed work should add interesting insight as to the mechanisms of interaction between eukaryotic and prokaryotic genomes resulting in the control of gene expression. This may provide fundamental information on controls of gene expression that could also hold true for host-pathogen or other medically important associations.

本研究的主要目的是提供一个更完整的在分子水平上，了解真核水蕨满江红及其内共生体，丝状蓝藻鱼腥藻分子和超微结构技术将是用于实现这一目标。两个基因的转录调控当鱼腥藻处于共生状态时，在拟议的工作细节。这些是g1 nA和psbA基因，编码谷氨酰胺合成酶和光系统II的32-kD蛋白。我们计划确定这些基因的结构并分析其表达在内共生体中。 g1 nA基因将被鉴定，并从一个基因组文库中分离，内共生体DNA 该基因的5 '侧翼和氨基末端区域将被识别并测序本发明使用的g1 nA启动子将鉴定用于转录的内共生体。谷氨酰胺合成酶将被定位在蓝藻细丝的单个细胞内，免疫电镜关于psbA基因，包含该psbA基因的基因的数目是已知的。将确定多基因家族。这个基因家族的所有成员都会从基因组文库中分离。独特的DNA片段可以作为 psbA基因家族不同成员的基因特异性探针将被识别。转录在细胞中的特定基因拷贝，将鉴定内共生体。此外，还将确定是否结果是在内共生体RNA中发现了不同大小的psbA转录物不同基因拷贝的特定加工、转录，或两者兼而有之。将确定psbA基因是否在异形胞中转录。此外，32-kD蛋白在蓝藻细胞内的定位将用免疫电子显微术阐明细丝。这项工作将提供有关异形胞的基本问题的答案蓝藻的分化过程，k和实际的机制，广义上的细胞分化：其中GS和32-kD 蛋白质的定位，以及它们的基因是如何被调控的。拟议工作应该增加有趣的洞察力之间的相互作用机制，真核生物和原核生物的基因组，表情这可能为基因调控提供基础信息，表达也可以适用于宿主病原体或其他医学重要协会。