Repair of lost 5' terminal sequences in tombusviruses: Rapid recovery of promoter- and enhancer-like sequences in recombinant RNAs.
Maintenance of genome integrity is of major importance for plus-stranded RNA viruses that are vulnerable to degradation by host ribonucleases or to replicase errors. We demonstrate that short truncations at the 5' end of a model Tomato bushy stunt virus (TBSV) RNA could be repaired during replication in yeast and plant cells. Although the truncations led to the loss of important cis-regulatory elements, the genome repair mechanisms led to the recovery of promoter and enhancer-like sequences in 92% of TBSV progeny. Using in vitro approaches, we demonstrate that the repaired TBSV RNAs are replication-competent. We propose three different mechanisms for genome repair: initiation of RNA synthesis from internal sequences and addition of nonviral nucleotides by the tombusvirus replicase; and via RNA recombination. The ability to repair cis-sequences makes the tombusvirus genome more flexible, which could be beneficial to increase the virus fitness and adaptation to new hosts.
Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA.
Yi
Y
Jiang
Chi-Ping
CP
Cheng
Elena
E
Serviene
Natalia
N
Shapka
Peter D
PD
Nagy
D002460:Cell Line; D016679:Genome, Viral; D042822:Genomic Instability; D011401:Promoter Regions, Genetic; D012313:RNA; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000821:virology; D017384:Sequence Deletion; D014026:Nicotiana / Q000821:virology; D017864:Tombusvirus / Q000235:genetics / Q000502:physiology*; D014779:Virus Replication
D012367:RNA, Viral; C039919:RNA, recombinant; D012313:RNA