Technological improvements for whole cell cryo-ET of respiratory syncytial virus infected cells

Abstract

Respiratory syncytial virus (RSV) is a common respiratory virus that causes over 235,000 hospitalizations in the US each year [1,2]. There are currently no approved treatments or vaccines. RSV virions are enveloped filamentous virions that are highly pleomorphic, but generally range in length from 1-4 µm with a diameter of ~130 nm [3]. The RSV matrix protein (M) has been crystallized as both a monomer and a dimer and experiments have shown that dimerization is required to assemble filamentous virions [4,5]. However, the organization of matrix within the virion has not been determined. The structure and organization matrix proteins or matrix protein equivalents of other paramyxoviruses has been solved by cryo-EM, cryo-ET, and sub-tomogram averaging [6][7][8].

Assembly of respiratory syncytial virus matrix protein lattice and its coordination with fusion glycoprotein trimers

“…However, assembly of filamentous virions or virus-like particles (VLPs) is inhibited by mutations that disrupt M dimerization 26 . We, and others, have previously published results from cryo-ET studies and STA of RSV virions indicating that M is arranged in a lattice of dimers 20 , 28 , 29 . Assembly of a membrane-associated matrix or matrix-like protein lattice has been shown for several other viruses 30 – 36 .…”