Exploration of sequence space as the basis of viral RNA genome segmentation

Elena Moreno, Samuel Ojosnegros, Juan García-Arriaza, Cristina Escarmís, Esteban Domingo, Celia Perales

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The mechanisms of viral RNA genome segmentation are unknown. On extensive passage of foot-and-mouth disease virus in baby hamster kidney-21 cells, the virus accumulated multiple point mutations and underwent a transition akin to genome segmentation. The standard single RNA genome molecule was replaced by genomes harboring internal in-frame deletions affecting the L- or capsid-coding region. These genomes were infectious and killed cells by complementation. Here we show that the point mutations in the nonstructural protein-coding region (P2, P3) that accumulated in the standard genome before segmentation increased the relative fitness of the segmented version relative to the standard genome. Fitness increase was documented by intracellular expression of virus-coded proteins and infectious progeny production by RNAs with the internal deletions placed in the sequence context of the parental and evolved genome. The complementation activity involved several viral proteins, one of them being the leader proteinase L. Thus, a history of genetic drift with accumulation of point mutations was needed to allow a major variation in the structure of a viral genome. Thus, exploration of sequence space by a viral genome (in this case an unsegmented RNA) can reach a point of the space in which a totally different genome structure (in this case, a segmented RNA) is favored over the form that performed the exploration.

Original languageEnglish
Pages (from-to)6678-6683
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number18
DOIs
StatePublished - 6 May 2014
Externally publishedYes

Keywords

  • Evolutionary transition
  • Mutant spectrum
  • Quasi-species
  • RNA virus evolution
  • Viral emergence

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