Localization and Importance of the Adenovirus E4orf4 Protein during Lytic Infection▿ †
| Autor: | Jose G. Teodoro, Peter Groitl, Marie-Joëlle Miron, Philip E. Branton, Suiyang Li, Paola Blanchette, Frédéric Dallaire, Thomas Dobner |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
Cytoplasm
viruses Recombinant Fusion Proteins Immunology Mutant Viral transformation Biology medicine.disease_cause Virus Replication Microbiology Virus Cell Line Viral Proteins VP40 Virology medicine Humans RNA Messenger Adenovirus infection Cell Nucleus Adenoviruses Human medicine.disease Molecular biology Virus-Cell Interactions Adenoviridae Viral replication Lytic cycle Insect Science RNA Viral Mutant Proteins Cell Nucleolus |
| Popis: | The human adenovirus type 5 (Ad5) E4orf4 product has been studied extensively although in most cases as expressed from vectors in the absence of other viral products. Thus, relatively little is known about its role in the context of an adenovirus infection. Although considerable earlier work had indicated that the E4orf4 protein is not essential for replication, a recent study using dl 359, an Ad5 mutant believed to produce a nonfunctional E4orf4 protein, suggested that E4orf4 is essential for virus growth in primary small-airway epithelial cells (C. O'Shea, et al., EMBO J. 24:1211-1221, 2005). Hence, to examine further the role of E4orf4 during virus infection, we generated for the first time a set of E4orf4 virus mutants in a common Ad5 genetic background. Such mutant viruses included those that express E4orf4 proteins containing various individual point mutations, those defective entirely in E4orf4 expression, and a mutant expressing wild-type E4orf4 fused to the green fluorescent protein. E4orf4 protein was found to localize primarily in nuclear structures shown to be viral replication centers, in nucleoli, and in perinuclear bodies. Importantly, E4orf4 was shown not to be essential for virus growth in either human tumor or primary cells, at least in tissue culture. Unlike E4orf4-null virus, mutant dl 359 appeared to exhibit a gain-of-function phenotype that impairs virus growth. The dl 359 E4orf4 protein, which contains a large in-frame internal deletion, clustered in aggregates enriched in Hsp70 and proteasome components. In addition, the late viral mRNAs produced by dl 359 accumulated abnormally in a nuclear punctate pattern. Altogether, our results indicate that E4orf4 protein is not essential for virus growth in culture and that expression of the dl 359 E4orf4 product interferes with viral replication, presumably through interactions with structures in the nucleus. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|