Affiliation:
1. Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
2. Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
Abstract
ABSTRACT
During entry into host cells, poliovirus undergoes a receptor-mediated conformational transition to form 135S particles with irreversible exposure of VP4 capsid sequences and VP1 N termini. To understand the role of VP4 during virus entry, the fate of VP4 during infection by site-specific mutants at threonine-28 of VP4 (4028T) was compared with that of the parental Mahoney type 1 virus. Three virus mutants were studied: the entry-defective, nonviable mutant 4028T.G and the viable mutants 4028T.S and 4028T.V, in which residue threonine-28 was changed to glycine, serine, and valine, respectively. We show that mutant and wild-type (WT) VP4 proteins are localized to cellular membranes after the 135S conformational transition. Both WT and viable 4028T mutant particles interact with lipid bilayers to form ion channels, whereas the entry-defective 4028T.G particles do not. In addition, the electrical properties of the channels induced by the mutant viruses are different from each other and from those of WT Mahoney and Sabin type 3 viruses. Finally, uncoating and/or cytoplasmic delivery of the viral genome is altered in the 4028T mutants: the 4028T.G lethal mutant does not release its genome into the cytoplasm, and genome delivery is slower during infection by mutant 4028T.V 135S particles than by mutant 4028T.S or WT 135S particles. The distinctive electrical characteristics of the different 4028T mutant channels indicate that VP4 sequences might form part of the channel structure. The different entry phenotypes of these VP4 mutants suggest that the ion channels may be related to VP4's role during genome uncoating and/or delivery.
Publisher
American Society for Microbiology
Subject
Virology,Insect Science,Immunology,Microbiology
Reference32 articles.
1. Basavappa, R., R. Syed, O. Flore, J. P. Icenogle, D. J. Filman, and J. M. Hogle. 1994. Role and mechanism of the maturation cleavage of VP0 in poliovirus assembly: structure of the empty capsid assembly intermediate at 2.9 A resolution. Protein Sci. 3 : 1651-1669.
2. Molecular Tectonic Model of Virus Structural Transitions: the Putative Cell Entry States of Poliovirus
3. Chow M. R. Basavappa and J. M. Hogle. 1997. The role of conformational transitions in poliovirus pathogenesis p. 157-186. In W. Chiu R. Garcea and R. Burnette (ed.) Structural biology of viruses. Oxford University Press Oxford United Kingdom.
4. Chow, M., J. F. Newman, D. Filman, J. M. Hogle, D. J. Rowlands, and F. Brown. 1987. Myristylation of picornavirus capsid protein VP4 and its structural significance. Nature 327 : 482-486.
5. Mouse adaptation determinants of poliovirus type 1 enhance viral uncoating
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