TY - JOUR TI - Cryo-electron tomography reveals novel features of a viral RNA replication compartment AU - Ertel, Kenneth J AU - Benefield, Desirée AU - Castaño-Diez, Daniel AU - Pennington, Janice G AU - Horswill, Mark AU - den Boon, Johan A AU - Otegui, Marisa S AU - Ahlquist, Paul A2 - Sundquist, Wesley I VL - 6 PY - 2017 DA - 2017/06/27 SP - e25940 C1 - eLife 2017;6:e25940 DO - 10.7554/eLife.25940 UR - https://doi.org/10.7554/eLife.25940 AB - 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. KW - flock house virus KW - RNA virus replication KW - mitochondrion KW - cryo-EM KW - tomography JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -