Functional characterization of the alphavirus TF protein
Autor(es): Snyder Jonathan E, Kulcsar Kirsten A, Schultz Kimberly L W, Riley Catherine P, Neary Jacob T, Marr Scott, Jose Joyce, Griffin Diane E, Kuhn Richard J
Resumo: Alphavirus dogma has long dictated the production of a discrete set of structural proteins during infection of a cell: capsid, pE2, 6K, - E1. However, bioinformatic analyses of alphavirus genomes (A. E. Firth, B. Y. Chung, M. N. Fleeton, - J. F. Atkins, Virol. J. 5:108, 2008) suggested that a ribosomal frameshifting event occurs during translation of the alphavirus structural polyprotein. Specifically, a frameshift event is suggested to occur during translation of the 6K gene, yielding production of a novel protein, termed transframe (TF), comprised of a C-terminal extension of the 6K protein in the -1 open reading frame (ORF). Here, we validate the findings of Firth - colleagues with respect to the production of the TF protein - begin to characterize the function of TF. Using a mass spectrometry-based approach, we identified TF in purified preparations of both Sindbis - Chikungunya virus particles. We next constructed a panel of Sindbis virus mutants with mutations which alter the production, size, or sequence of TF. We demonstrate that TF is not absolutely required in culture, although disrupting TF production leads to a decrease in virus particle release in both mammalian - insect cells. In a mouse neuropathogenesis model, mortality was <15% in animals infected with the TF mutants, whereas mortality was 95% in animals infected with the wild-type virus. Using a variety of additional assays, we demonstrate that TF retains ion-channel activity analogous to that of 6K - that lack of production of TF does not affect genome replication, particle infectivity, or envelope protein transit to the cell surface. The TF protein therefore represents a previously uncharacterized factor important for alphavirus assembly.
Imprenta: Journal of Virology, v. 87, n. 15, p. 8511-8523, 2013
Identificador do objeto digital: 10.1128/JVI.00449-13
Descritores: Chikungunya virus - Biosynthesis ; Chikungunya virus - Cell ; Chikungunya virus - Cytopathology ; Chikungunya virus - Genome ; Chikungunya virus - Pathogenesis ; Chikungunya virus - Protein synthesis ; Chikungunya virus - Proteins ; Chikungunya virus - Viral infections ; Chikungunya Virus - Virus ; Chikungunya virus - Epidemiology ; Chikungunya virus - Public health
Data de publicação: 2013
