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.
Jiang
Yi
Y
Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA.
Cheng
Chi-Ping
CP
Serviene
Elena
E
Shapka
Natalia
N
Nagy
Peter D
PD
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