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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #256894
Title: A Tymovirus with an Atypical 3´-UTR Illuminates the Possibilities for 3´-UTR Evolution

Author
item TZANETAKIS, I - University Of Arkansas
item TSAI, C-H - Oregon State University
item Martin, Robert
item DREHER, T - Oregon State University

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2009
Publication Date: 8/16/2009
Citation: Tzanetakis, I.E., Tsai, C., Martin, R.R., Dreher, T.W. 2009. A tymovirus with an atypical 3´-UTR illuminates the possibilities for 3´-UTR evolution. Virology. 392:238-245.

Interpretive Summary: The complete genomic sequence of Dulcamara mottle virus (DuMV) is reported, and it confirms that it is a member of the Tymovirus genus. The sequence data supports previous data that suggested DuMV was a Tymovirus based on physical and biological properties. The 5´ untranslated region (UTR) and coding regions of DuMV RNA have characteristics of tymoviral RNAs. However, the 3´-UTR is the longest and most unusual reported for a tymovirus. Previously, it was reported that DuMV had a poly(A) tail at the 3' end rather than a t-RNA like structure found on all other Tymoviruses. The data presented here shows that there is an internal poly(A) tract that was likely mistaken for the 3' end in the previous report. A full-length clone of DuMV was constructed and shown to be capable of producing infectious DuMV genomic RNAs. A chimeric virus that consisted of Turnip yellow mosaic virus (TYMV) genome but with the DuMV 3´-UTR in place of the normal t-RNA like structure was constructed to investigate the ability of the TYMV replication proteins to amplify RNAs the modified 3' end. The chimeric virus was shown to be capable of replication and systemic spread in plants, although amplification was very limited. These experiments suggest the way in which DuMV may have evolved from a typical tymovirus and illuminate the ways in which viral 3´-UTRs in general can evolve.

Technical Abstract: We report the complete genome sequence of Dulcamara mottle virus (DuMV), confirming its membership within the Tymovirus genus, which was previously based on physical and pathology evidence. The 5´ untranslated region (UTR) and coding region of DuMV RNA have the typical characteristics of tymoviral RNAs. In contrast, the 3´-UTR is the longest and most unusual yet reported for a tymovirus, possessing an internal poly(A) tract, lacking a 3´-tRNA-like structure (TLS) and terminating at the 3´-end with –UUC instead of the typical –CC(A). An expressible cDNA clone was constructed and shown to be capable of producing infectious DuMV genomic RNAs with -UUC 3´-termini. A chimeric Turnip yellow mosaic virus (TYMV) genome bearing the DuMV 3´-UTR in place of the normal TLS was constructed in order to investigate the ability of the TYMV replication proteins to amplify RNAs with –UUC instead of –CC(A) 3´ termini. The chimeric genome was shown to be capable of replication and systemic spread in plants, although amplification was very limited. These experiments suggest the way in which DuMV may have evolved from a typical tymovirus, and illuminate the ways in which viral 3´-UTRs in general can evolve.