📄 Analyses of coronavirus assembly interactions with interspecies membrane and nucleocapsid protein chimeras

© 2016, American Society for Microbiology. The coronavirus membrane (M) protein is the central actor in virion morphogenesis. Morganizes the components of the viral membrane, and interactions ofMwith itself and with the nucleocapsid (N) protein drive virus assembly and budding. In order to further define M-M and M-N interactions, we constructed mutants of the model coronavirus mouse hepatitis virus (MHV) in which all or part of theMprotein was replaced by its phylogenetically divergent counterpart from severe acute respiratory syndrome coronavirus (SARS-CoV). We were able to obtain viable chimeras containing the entire SARS-CoVMprotein as well as mutants with intramolecular substitutions that partitionedMprotein at the boundaries between the ectodomain, transmembrane domains, or endodomain. Our results show that the carboxy-terminal domain of N protein, N3, is necessary and sufficient for interaction withMprotein. However, despite some previous genetic and biochemical evidence that mapped interactions with N to the carboxy terminus of M, it was not possible to define a short linear region ofMprotein sufficient for assembly with N. Thus, interactions with N protein likely involve multiple linearly discontiguous regions of theMendodomain. The SARS-CoVM chimera exhibited a conditional growth defect that was partially suppressed by mutations in the envelope (E) protein. Moreover, virions of theMchimera were markedly deficient in spike (S) protein incorporation. These findings suggest that the interactions ofMprotein with both E and S protein are more complex than previously thought.

keywords 🔗 severe acute (1373) 🔗 syndrome coronavirus (1074) 🔗 hepatitis virus (437) 🔗 coronavirus mouse (66) 🔗 mouse hepatitis (371) 🔗 carboxy terminus (13) 🔗 transmembrane domain (51) 🔗 respiratory syndrome (2004) 🔗 findings suggest (77) 🔗 acute respiratory (1734)

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