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Cryo-electron tomography reveals novel features of a viral RNA replication compartment.

Kenneth J ErtelDesirée BenefieldDaniel Castaño-DiezJanice G PenningtonMark HorswillJohan A den BoonMarisa S OteguiPaul G Ahlquist
Published in: eLife (2017)
Positive-strand RNA viruses, the largest genetic class of viruses, include numerous important pathogens such as Zika virus. These viruses replicate their RNA genomes in novel, membrane-bounded mini-organelles, but the organization of viral proteins and RNAs in these compartments has been largely unknown. We used cryo-electron tomography to reveal many previously unrecognized features of Flock house nodavirus (FHV) RNA replication compartments. These spherular invaginations of outer mitochondrial membranes are packed with electron-dense RNA fibrils and their volumes are closely correlated with RNA replication template length. Each spherule's necked aperture is crowned by a striking cupped ring structure containing multifunctional FHV RNA replication protein A. Subtomogram averaging of these crowns revealed twelve-fold symmetry, concentric flanking protrusions, and a central electron density. Many crowns were associated with long cytoplasmic fibrils, likely to be exported progeny RNA. These results provide new mechanistic insights into positive-strand RNA virus replication compartment structure, assembly, function and control.
Keyphrases
  • zika virus
  • nucleic acid
  • electron microscopy
  • sars cov
  • drug delivery
  • high resolution
  • dna methylation
  • genome wide
  • small molecule
  • antimicrobial resistance