Complete Genome Sequence and Genetic Organization of a Taiwan Isolate of Zucchini yellow mosaic virus

矮南瓜黃化嵌紋病毒台灣分離侏之基因體核酸序列及其基因組成分析

林詩舜(Shih-Shun Lin) ； 侯豐男(Roger F.Hou) ； 葉錫東(Shyi-Dong Yeh)

《Botanical Bulletin of Academia Sinica》 42卷4期 (2001/10) Pp. 243-250

https://doi.org/10.7016/BBAS.200110.0243

摘要

矮南瓜黃化嵌紋病毒台灣分離侏(ZYMV TW-TN3)之全長基因體核酸序列經由五個互補去氧核糖核酸之選殖株全部解序完畢，其全長序列不包含poly(A)爲9591個核苷酸。經電腦全長序列顯示其基因體核酸可轉譯出一個大的轉譯架構，此轉譯架構可産生一個含有3080胺基酸的複合大蛋白體。將已發表之加州、雷優尼島(Reunion Island)及新加坡ZYMV分離株與TW-TN3做比較，彼此之間的5′非轉譯區與3′非轉譯區之核酸相似度分別爲61.6-83.3%及90.4-95.7%。而彼此之間的P1蛋白是差異性最大，其胺基酸楨度爲59-93%。分析TW-TN3與其它已知序列之六個ZYMV分離株之P1蛋白演化關係，顯示PI蛋白可分成四個主要之基因型 。TW-TN3屬於第一基因型 ，美國分離株屬於第二基因型，雷優尼島與新加坡分離侏分別屬於第三與第四基因型。由演化關係圖中顯示第一基因型 與第二基因型的親源關係較爲接近，因此台灣與美國分離株可能由共同祖先所演化而來，分析四個ZYMV分離株之NIa蛋白裂解酵素切位，其主要之裂解位置在Q-S及E-S雙勝肽序列，並且推測其NIa辨識序列爲V-x-x-(Q-E)-(S,A,G).緫結TW-TN3所轉譯的基因組成由5′至3′依序爲Vpg/5′引導序列/P1(36kDa)/HCPro(52kDa)/P3(40kDa)/6K1(6kDa)/CIP(71kDa)/6K2(6kDa)/NIa-Vpg(22kDa)/NIa-Pro(27kDa)/NIb(60kDa)/CP(31kDa)-3′非轉譯區-poly(A)。

關鍵字

ZYMV分離株 ； 全長基因體核酸序列 ； 基因組成

並列摘要

The complete nucleotide sequence of the RNA genome of a Taiwan isolate of Zucchini yellow mosaic virus (ZYMV TW-TN3) was determined from five overlapping cDNA clones 9591 nucleotides in length excluding the poly (A) tail. Computer analysis of the sequence revealed a large open reading frame (ORF) that encodes a polyprotein of 3080 amino acids. Comparison of the gene products of TW-TN3 with those of the reported California (CA), Reunion Island (RU), and Singapore (S) isolates of ZYMV revealed that P1 protein is most variable, with amino acid identities of 59.0-93.2%. The 5′untranslated region (UTR) of TW-TN3 shares 61.6-83.3% nucleotide identities, and the 3′UTR shares 90.4-95.7% nucleotide identities, with those of the other isolates. A phylogenetic tree derived from the sequences of P1 proteins of TW-TN3 and the other six reported ZYMV isolates revealed four major genotypes. TW-TN3 was classified in genotype I, and US isolates were in genotype II. The Reunion Island and Singapore isolates were separated into genotypes III and IV, respectively. The distance relationships of P1 protein of genotype I were closer to genotype II, indicating that the Taiwan and US isolates may evolve from the same ancestor. Analyses on the cleavage sites of the C-terminal halves of the polyproteins of TW-TN3, CA, RU, and S isolates revealed that NIa protease cleaves at Q-S, and E-S dipeptide sequences, with a consensus sequence of V-x-x-(Q, E)/(S, A, G). The genetic organization of TW-TN3 was concluded as Vpg/5′ leader/P1 (36kDa)/HC Pro (52kDa)/P3 (40kDa)/6Kl (6kDa)/CIP (71kDa)/6K2 (6kDa)/NIa-Vpg (22kDa)/NIa-Pro (27kDa)/NIb (60kDa)/CP (31kDa)/3′ UTR-poly(A) tract.

並列關鍵字

Genetic organization ； Genome sequence:ZYMV isolates