Localization of cis-acting sequences essential for cymbidium ringspot tombusvirus defective interfering RNA replication

• Published in: Journal of general virology 1995-09, Vol.76 (9), p.2311-2316
• Main Authors: Havelda, Zoltan, Dalmay, Tamas, Burgyan, Jozsef
• Format: Article
• Language: English
• Subjects: Base Sequence; Chromosome Mapping; cymbidium ringspot virus; Molecular Sequence Data; RNA, Viral - biosynthesis; RNA, Viral - genetics; Sequence Deletion; Tombusvirus - genetics; Tombusvirus - physiology; Virus Replication
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-76-9-2311

Agricultural Biotechnology Center, Plant Science Institute, PO Box 411, 2101 Gödöllõ, Hungary The smallest defective interfering RNA (DI-2) of cymbidium ringspot tombusvirus (CyRSV) was used to identify the cis -acting sequences necessary for its replication by making a series of deletions throughout the 404 nt long molecule and testing the biological activity of mutants. Deletion or substitution of the conserved sequence blocks (A, B and C) always yielded inactive molecules. The deletion of only a few nucleotides could be tolerated beyond the natural deletion sites in blocks A and B. However, either half of block C1 (34 nt) and the first 25 nt of C2 (102 nt) could be deleted without loss of infectivity. It was also demonstrated that either one of the two halves of block C1 was specifically required for replication. We suggest that the last 77 nt of the viral genome and either half of block C1 represent the complementary strand promoter sequence recognized by the viral replicase. * Author for correspondence. Fax [phone]. e-mail [e-mail] Received 28 February 1995; accepted 9 May 1995.