The Morphology and Assembly of Respiratory Syncytial Virus Revealed by Cryo-Electron Tomography

Zunlong Ke,Jeannette Taylor,Martin Moore,Cheri Hampton,Hong Yi,Devi Rajan,Tina Hartert,Elizabeth Wright,R Peebles,Raven Shah,Joshua Strauss,Mengtian Jin,Christina Rostad,Fredrick Leon,Christopher Stobart,Rebecca Dillard,Larry Anderson,Barney Graham,Tatiana Chirkova

doi:10.3390/v10080446

Abstract

Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease in young children. With repeat infections throughout life, it can also cause substantial disease in the elderly and in adults with compromised cardiac, pulmonary and immune systems. RSV is a pleomorphic enveloped RNA virus in the Pneumoviridae family. Recently, the three-dimensional (3D) structure of purified RSV particles has been elucidated, revealing three distinct morphological categories: spherical, asymmetric, and filamentous. However, the native 3D structure of RSV particles associated with or released from infected cells has yet to be investigated. In this study, we have established an optimized system for studying RSV structure by imaging RSV-infected cells on transmission electron microscopy (TEM) grids by cryo-electron tomography (cryo-ET). Our results demonstrate that RSV is filamentous across several virus strains and cell lines by cryo-ET, cryo-immuno EM, and thin section TEM techniques. The viral filament length varies from 0.5 to 12 μm and the average filament diameter is approximately 130 nm. Taking advantage of the whole cell tomography technique, we have resolved various stages of RSV assembly. Collectively, our results can facilitate the understanding of viral morphogenesis in RSV and other pleomorphic enveloped viruses.

Highlights

Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease in young children including bronchiolitis and pneumonia
We demonstrate that RSV particles are filamentous when produced from virus-infected human-derived cell lines and virus-infected polarized normal human bronchial epithelial (NHBE) cells
The transmission electron microscopy (TEM) images demonstrate that RSV particles produced by and extending from the infected-NHBE cells are filamentous (Figure all,results the results suggest morphologyisisfilamentous filamentous in in both both transformed and In 5)

Summary

Introduction

Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease in young children including bronchiolitis and pneumonia. With repeat infections throughout life, RSV causes substantial disease in older children and adults with compromised cardiac, pulmonary and immune systems, as well as the elderly. Complications due to the disease can lead to death [1,2,3]. With significant morbidity and mortality in the United States and disproportionately high-levels worldwide, it has been a high priority for vaccine development for over 50 years but no licensed vaccine is yet available [4,5]. RSV is an enveloped, negative sense, single-stranded RNA virus in the family of Pneumoviridae [1,6]. The ~15.2 kb genome of RSV contains 10 open reading frames, encoding nine structural proteins and two non-structural proteins. The attachment glycoprotein (G), fusion glycoprotein (F), and the small hydrophobic protein (SH) are anchored in the viral membrane with the majority of the protein present on the exterior of the membrane; the matrix protein (M) lines the interior of the viral membrane

Methods

Results

Conclusion