Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2011
Publication Date: 5/1/2011
Citation: Weng, Y., Lu, W., Harmon, A., Xiang, X., Deng, Q., Song, M., Wang, D., Yu, Q., Li, F. 2011. The cellular endosomal sorting complex required for transport pathway is not involved in avian metapneumovirus budding in a virus-like-particle expression system.. Journal of General Virology. 92:1205-1213. Interpretive Summary: Avian metapneumovirus is an economically important pathogen of turkeys with a worldwide distribution. In the United States, avian metapneumovirus infection was first reported in Colorado in 1996, subsequently in Minnesota, resulting in significant economic losses. To understand the virus life cycle, we studied the requirements of viral proteins for virus budding. We found that the matrix protein, a major structural component of the virus particles, by its self was not sufficient to form virus-like-particles. Two other viral structural components, the nucleoprotein and fusion protein, were required for the incorporation of the matrix protein into the virus-like-particles. These results assist in understanding the virus maturation mechanism and designing a strategy to prevent the disease.
Technical Abstract: Avian metapneumovirus (AMPV) is a paramyxovirus that principally causes respiratory disease and egg production drops in turkeys and chickens. Together with its closely related human metapneumovirus (HMPV), they comprise the genus metapneumovirus in the Paramyxoviridae family. Little is currently known about the mechanisms involved in the budding of metapneumovirus. By using avian metapneumovirus as a model system, we showed that the matrix protein (M) by itself was insufficient to form virus-like-particles (VLPs). The incorporation of M into VLPs was shown to occur only when both the viral nucleoprotein (N) and the fusion (F) proteins were coexpressed. Furthermore, we provided the evidence indicating that two YSKL and YAGL segments encoded within the M protein were not a functional late domain, and the endosomal sorting complex required for transport (ESCRT) machinery was not involved in metapneumovirus budding, consistent with a recent observation that human respiratory syncytial virus (HRSV), closely related to HMPV, uses a ESCRT-independent budding mechanism. Taken together, these results suggest that metapneumovirus budding is independent of ESCRT pathway and the minimal budding machinery described here will aid our future understanding of metapneumovirus assembly and egress.