TRANSCRIPTIONALLY REGULATED GENES IN A SYMBIOSIS

拟议研究的主要目标是提供一个更完整的 在分子水平上理解分子间的相互作用 真核水生蕨满江红及其内生丝状共生体 蓝藻鱼腥藻。分子和超微结构技术将是 用来实现这一目标。转录调控的两个基因 当鱼腥藻处于共生状态时，将具有更大的特点 在拟议的工作中的细节。这些是g1nA和PSBA基因，它们 编码谷氨酰胺合成酶和光系统II的32-kD蛋白。 计划确定这些基因的结构并分析其表达 在内生共生体中。 G1nA基因将从日本血吸虫基因组文库中鉴定和分离 内共生菌DNA。该基因的5‘侧翼和氨基末端区域 将被识别和测序。中国使用的g1nA启动子(S) 将鉴定转录的内共生体。谷氨酰胺合成酶 将定位于蓝藻细丝的单个细胞内 免疫电子显微镜。 关于PSBA基因，组成这一基因的基因数量 多基因家族将被确定。这个基因家族的所有成员都会 从基因组文库中分离出来。独特的DNA片段可以作为 针对PSBA基因家族不同成员的基因特异性探针将 被指认出来。特定的基因拷贝在转录于 内生菌将被鉴定出来。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基因是否在异形胞中转录。 此外，32-kD蛋白在蓝藻细胞内的定位 细丝将用免疫电子显微镜进行鉴定。 这项工作将提供有关杂胞的基本问题的答案 蓝藻的分化过程，K和确实的机制 最广义的细胞分化：GS和32-KD在哪里 蛋白质的定位，以及它们的基因是如何调节的。拟议中的工作 应该增加对相互作用机制的有趣洞察力 真核和原核基因组导致基因控制 表情。这可能为基因调控提供基础信息。 对于宿主病原体或其他医学上也适用的表达 重要的联想。

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.