https://scholars.lib.ntu.edu.tw/handle/123456789/139472
標題: | 逆境蛋白質功能性研究:阿拉伯芥AtHVA22蛋白質之細胞內定位分析 Functional Studies of a Stress Protein Family: Subcellular Localizations of AtHVA22a-e Proteins in Arabidopsis |
作者: | 呂詠玉 Lu, Yung-Yu |
關鍵字: | HVA22;細胞內定位;綠色螢光蛋白;逆境誘導蛋白;內膜系統;囊泡運輸;內質網;高基氏體;subcellular localization;GFP;stress-inducible proteins;endomembrane system;vesicle trafficking;ER (endoplasmic reticulum);Golgi apparatus | 公開日期: | 2008 | 摘要: | HVA22是個會受到離層酸(ABA)與逆境誘導表現的蛋白質,最早是從大麥的糊粉層細胞中找到。根據序列比對分析,目前只在真核生物中可找到HVA22的同源基因。其中,酵母菌中的同源基因Yop1p被認為與細胞內囊泡運輸有關,並已證實在活體試驗下可穩定微管蛋白的形成,並影響內質網絡的構築。因此,推測這些DP1/TB2/HVA22家族蛋白可能參與植物細胞內的囊泡運輸。在阿拉伯芥中,已找到11個HVA22的同源基因,包含AtHVA22a-k。其中一群同源基因AtHVA22a-e親源關係較接近大麥中的HVA22跟酵母菌中的Yop1,並都預測有三個模鑲嵌區塊 (transmembrane domain);另外六個同源基因中,AtHVA22f, g, k為偽基因,而AtHVA22h-j則沒有被預測到有明顯的模鑲嵌區塊。了釐清阿拉伯芥AtHVA22蛋白質的功能,我們藉由在阿拉伯芥原生質體中暫時性表現AtHVA22a-e與綠色螢光蛋白形成的融合蛋白質(AtHVA22a-e:GFP),利用共軛焦顯微鏡觀察螢光蛋白表現的位置,以分析阿拉伯芥HVA22蛋白質之細胞內定位。目前的研究結果發現阿拉伯芥AtHVA22a, b, c, d 和e在植物細胞中各自有特殊的細胞內定位。其中,AtHVA22b和AtHVA22e位在高基氏體,AtHVA22d同時位於高基氏體和內質網,而AtHVA22a和AtHVA22c在細胞中的定位則尚未釐清,但他們可能與AtHVA22b有交互作用。綜合前人研究,已知AtHVA22a-e會受到離層酸及非生物性逆境調控不同組織的基因表現,我們推測AtHVA22a-e可能參與調控逆境誘導的囊泡運輸,以幫助植物抵抗逆境。其中,阿拉伯芥的AtHVA22b, AtHVA22d 和 AtHVA22e可能參與細胞內由內質網經高基氏體運輸的囊泡運輸途徑,而AtHVA22a與AtHVA22c在非逆境處理下則可能參與其他囊泡運輸途徑。 HVA22 is an ABA- and stress-inducible protein that was first isolated from barley aleurone cells. Homologues of HVA22 have been found only in eukaryotes. The yeast homolog, Yop1 is proposed to be involved in vesicle trafficking, and has been shown to stabilize tubule formation to comprise ER network in vivo. As a result, these DP1/TB2/HVA22 family proteins are proposed to be involved in vesicle trafficking pathways in plant cells. There are 11 HVA22 homologues in Arabidopsis, designed as AtHVA22a-k. Among these homologues, AtHVA22a-e contain three potential transmembrane domains, and are phylogenetically closer to yeast Yop1 and barley HVA22. However, AtHVA22f, g, k are pseudogenes and AtHVA22 h-j do not contain significant potential transmembrane domains. o investigate the functions of AtHVA22a-e proteins in vivo, we generated AtHVA22a-e:GFP fusion proteins and transiently expressed them in Arabidopsis mesophyll protoplasts. By confocal microscopy, we investigated the subcellular localizations of AtHVA22a-e proteins. Our observations indicated that each of AtHVA22a, b, c, d and e had specific cellular localizations. AtHVA22b and e were localized to Golgi apparatus. AtHVA22d was localized to both endoplasmic reticulum (ER) and Golgi apparatus. The subcellular localizations of AtHVA22a and c remained unclear; however, they seemed to interact with AtHVA22b. These results indicated that each of AtHVA22a-e proteins had a specific role in vesicular trafficking. Combined with previous studies of tissue-specific and differential expression levels of AtHVA22 genes in response to ABA and abiotic stresses, we propose that AtHVA22a-e may function in stress-induced vesicular trafficking to establish stress tolerance in plants. In particular, AtHVA22b, d and e may be involved in the ER-Golgi trafficking pathways. On the other hand, AtHVA22a and c are likely not involved in the same pathway under normal condition. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/181932 |
顯示於: | 植物科學研究所 |
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ntu-97-R95b42008-1.pdf | 23.32 kB | Adobe PDF | 檢視/開啟 |
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