TRANSCRIPTIONALLY REGULATED GENES IN A SYMBIOSIS

本研究的主要目标是提供更完整的 在分子水平上理解物质之间的相互作用 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 用于实现这一目标。 两个受转录调控的基因 当鱼腥藻处于共生状态时，将具有更大的特征 拟议工作的详细信息。 这些是 g1nA 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。 g1nA 基因将从基因组文库中鉴定并分离 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。 使用的 g1nA 启动子 将鉴定转录的内共生体。 谷氨酰胺合成酶 将定位在蓝藻丝的单个细胞内 免疫电子显微镜。 对于psbA基因，包含该基因的基因的数量 多基因家族将被确定。 该基因家族的所有成员都会 从基因组文库中分离。 独特的 DNA 片段可用作 针对 psbA 基因家族不同成员的基因特异性探针将 被识别。 转录的特定基因拷贝 内共生体将被识别。 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 转录本 特定加工、不同基因拷贝的转录或两者兼而有之。 将确定psbA基因是否在异形细胞中转录。 此外，蓝藻细胞内 32-kD 蛋白质的位置 细丝将通过免疫电子显微镜来阐明。 这项工作将为有关异形体的基本问题提供答案 蓝藻的分化过程及其机制 最广泛意义上的细胞分化：GS 和 32-kD 在哪里 蛋白质的位置以及它们的基因如何受到调节。 拟议的工作 应该增加关于之间相互作用机制的有趣见解 真核和原核基因组导致基因控制 表达。 这可能提供有关基因控制的基本信息 表达也可能适用于宿主病原体或其他医学 重要的协会。

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.