https://scholars.lib.ntu.edu.tw/handle/123456789/96190
標題: | 竹嵌紋病毒之分子生物學─竹嵌紋病毒缺失性RNA之研究 | 作者: | 張雅君 | 關鍵字: | 竹嵌紋病;竹嵌紋病毒;缺失性RNA;Bamboo Mosaic;BaMV;Defective RNA | 公開日期: | 2001 | 出版社: | 臺北市:國立臺灣大學植物病理與微生物學系暨研究所 | 摘要: | 為研究竹嵌紋病毒(Bamboo mosaic virus,簡稱BaMV)的缺失性RNA,本實驗室根 據以往菸草原生質體接種實驗結果,選擇增殖能力最佳的D20 作為野生株,構築四種 frame shift 突變株,使終止碼提前出現;如此即可在不影響RNA 序列和二度結構下,轉 譯出不同長度之複製酵素。經菸草原生質體接種實驗證實,BaMV 缺失性RNA 的轉譯 架構長度必須不少於99 個氨基酸,才具有被增殖的能力,且轉譯長度與其增殖能力成 正相關。利用來自BaMV 鞘蛋白基因或是以EGFP 外來基因取代D20 原有之轉譯架構, 雖然仍保有相似長度之轉譯架構,但卻無法維持其增殖能力,顯示除了轉譯架構的長度 外,轉譯架構中的序列部份亦有其重要性。將D20 與無複製能力之D20-CP 或 D20-EGFP,與BaMV 同時接種至菸草原生質體,結果發現D20 無法挽救兩者所喪失的 能力。移除不同長度及不同區域之D20 序列發現,缺失性RNA 至少需保有BaMV 5’端 nt 1-551 與3’端nt 936-1118 之序列片段才能增殖;當移除序列nt 388-551 時會使D20 增 殖能力大幅下降,因此其中應含有與增殖能力相關的序列(cis-acting sequence)。 In order to study the defective RNAs (D RNAs) of Bamboo mosaic virus (BaMV), we chose D20, which had the highest level of accumulation in previous tobacco protoplast assay, as wild type to construct four frame shift mutants. These mutants with introduced pre-terminated stop codons had similar RNA sequences and secondary structures, but different length of open reading frame (ORF). The results indicated that the ORF of D RNAs must be no less than 99 amino acids in order to maintain their biological activities and the level of accumulation was correlated with the length of ORF. When the sequences of the ORF was replaced by BaMV coat protein (CP) gene or foreign EGFP gene, the mutants, D20-CP and D20-EGFP, were nonviable although their ORF lengths were similar to D20. The above results indicated that not only the lengths of the ORF but also the sequences within ORF are important for the accumulation of BaMV D RNA. When D20 were co-inoculated with D20-CP or D20-EGFP to test if it could complement the replication of both mutants, the - 2 - result was negative. According to the experimental results of D20 deletion mutants, the minimum sequences required for biological activities of BaMV D RNAs are from regions nt 1-551 and nt 936-1118. D20 mutants with nt 388-551 deleted greatly decreased the level of accumulation and suggested that these deleted sequences maybe contain cis-acting sequence of replication |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/17674 | 其他識別: | 892311B002092 | Rights: | 國立臺灣大學植物病理與微生物學系暨研究所 |
顯示於: | 植物病理與微生物學系 |
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