感染柑桔裂皮病类病毒的爪哇三七细胞内的两种闭环RNA

TWO KINDS OF CIRCULAR RNA IN GYNURA AURANTIACA D. C.CELL INFECTED WITH CJTRUS EXOCORTIS VIROID

用双向聚丙烯酰胺凝胶电泳—银染法对爪哇三七(Gynura aurantioca, D. C.)进行生化分析,发现在健康爪哇三七细胞质中有一种闭环RNA(Cytoplasmic small circular RNA,简称cscRNA),它的电泳行为与柑桔裂皮病类病毒(CitruS Exocortis Viroid,简称CEV)相似,而点杂交结果显示它的一级结构与类病毒RNA的中心保守区核酸序列没有同源性。进一步分析细胞不同组分的RNA,发现cscRNA仅存在于细胞质中,并与季节的变化有密切关系。在CEV感染的爪哇三七细胞中,可测出CEV-RNA和cscRNA两种闭环RNA分子,但细胞核内仅能检出CEV-RNA一种分子,它与类病毒的中心保守区有明显的同源性。检测CEV感染时,可用细胞核RNA进行测定,以排除细胞质小分子闭环RNA的干扰。

By two-dimensional electrophoretic technique, a cytoplasmic small circular RNA (cscRNA ) was found in Gynura aurantiaca D.C. leaf. A band similar to that of citrus exocortis viroid ( CEV ) was detected. False result is often caused in detecting CEV in Gynura aurantiaca D.C. by the two-dimensional electrophoretic technique. The result of dot-blotting hyb- ridization, however, showed that there was no detectable sequence homolo-gy between cscRNA and the conserved central region of CEV. Further analysis by polyacrylamide gel electrophoresis ( PAGE ) of nucleic acid that was obtained from the Gynura aurantiaca cell nuclei, revealed no cscRNA in nuclei-rich preparations from healthy Gynura auratiaca D.C.,but CEV was found in nuclei-rich preparations of CEV-infected Gynura auantiaca D.C.. Moreover, the appearance of cscRNA was related with change of seasons, being undetectable in August and September.The above method enables us to avoid spurious result caused by the presence of cscRNA. Therefore, it can be used to diagnose accurately whether Gynura aurantiaca D.C. is infected by CEV or not.