台灣新發現之大鼠小病毒的分子特徵

Abstract

囓齒類動物小病毒 (Rodent parvoviruses)為囓齒類實驗動物中常見病原之一，已有相關研究指出此類病毒會影響in vivo和in vitro的實驗結果。本實驗室在2008年以PCR方式進行小規模實驗大鼠疾病調查，檢測結果發現台灣的實驗大鼠部分呈現囓齒類動物小病毒陽性反應。本研究將前次調查中檢出的陽性檢體，依據囓齒類動物小病毒的高保留區和高特異區之病毒基因序列所設計的引子，進行病毒基因複製與序列分析，將此台灣型的囓齒類動物小病毒之核苷酸序列及預期胺基酸序列與已知的囓齒類動物小病毒進行比較與分析。藉此基因複製及序列分析，完成總長約4759個核苷酸的基因序列，其中包含兩個大的轉譯讀窗(open reading frame, ORF)。序列分析後結果顯示，由台灣實驗大鼠所檢出的囓齒類動物小病毒與其他已知的囓齒類動物小病毒同樣具有rodent parvovirus的病毒調控轉錄及轉錄區域的特徵。在核苷酸與預期胺基酸序列分析方面，台灣型的囓齒類動物小病毒與目前已發現的Rat parvovirus, RPV-1a and RPV-1b 極為相似，但與RPV/UT及其他已知的囓齒類動物小病毒明顯不同。並經由演化樹之分析發現，台灣型的大鼠小病毒應歸屬於RPV-1族群，並命名為RPV-1c。本研究為首篇於美國以外地區發現的RPV-1的報告，並對病毒基因及蛋白質進行進一步的序列比較分析。

Rodent parvoviruses are one of the most prevalent infectious agents in the laboratory rodent and have been documented to interfere with in vivo and in vitro research. A newly recognized rat parvovirus (RPV) distinct from the prototypic RPV was recently identified in naturally infected laboratory rats in Taiwan. In present study, the viral DNA sequence and the predicted amino acid sequences of the new variant of RPV were determined and compared to RPV-1a, RPV-1b, RPV/UT and other rodent parvoviruses. DNA sequence fragment a total of 4759 nucleotides in length, encompassing two large and several small open reading frames (ORFs) were determined. Nucleotide and amino acid sequence comparisons showed that the variant of RPV is most closely related to RPV-1a and RPV-1b and distinctly different from RPV/UT and other rodent parvoviruses. The virus was designated rat parvovirus type 1c (RPV-1c). The phylogenetic analyses reveal that RPV-1c is a variant of RPV-1 group, including RPV-1a and RPV-1b. RPV-1c is the first molecularly characterized RPV variant identified outside of USA.