Virology 226, 153-160 (1996) Article no. 0641

In Vivo Repair of 3'-End Deletions in a TCV Satellite RNA May Involve Two Abortive Synthesis and Priming Events

Clifford D. Carpenter and Anne E. Simon

Department of Biochemistry and Molecular Biology and the Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003

RNA viruses that do not have the stabilizing features of poly(A) tails or amino acids covalently linked to their 3' ends must develop other means for protecting or repairing their genomes from damage caused by cellular RNases. We previously found that deletions in the single-stranded tails of a satellite RNA (sat-RNA D) associated with turnip crinkle virus are repaired in viva (C. D. Carpenter and A. E. Simon, 1996, J. Virol. 70, 478 -- 486). We now extend this analysis to show that sat-RNA D transcripts with 3'-end deletions of 5 bases give rise to wild-type sat-RNA, while deletions of 6 to 11 bases result in sat-RNA with additional deletions to the -- 14 position joined to internal TCV genomic RNA (or other) sequence followed by replacement of the terminal C,,UGC,, motif. In addition, we have determined that the selection of internal TCV sequence used in the repair of sat-RNA D 3' ends is not random and generation of these short TCV segments likely involves primer-mediated synthesis of abortive products facilitated by base-pairing between internal regions of TCV genomic RNA and oligoribonucleotides generated by abortive cycling from the 3' end of the TCV genome.