Highly Acidic C-Terminal Region of Cytomegalovirus pUL96 Determines Its Functions during Virus Maturation Independently of a Direct pp150 Interaction
| Autor: | Ritesh Tandon, Edward S. Mocarski, Teal M. Brechtel |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Molecular Sequence Data
Immunology Cytomegalovirus Biology Virus Replication Microbiology Virus Viral Matrix Proteins Viral Proteins VP40 Virology Virus maturation Humans Amino Acid Sequence Viral matrix protein Structure and Assembly Point mutation Phosphoproteins Resistance mutation Protein Structure Tertiary NS2-3 protease Viral replication Insect Science Cytomegalovirus Infections Sequence Alignment Protein Binding |
| Zdroj: | Journal of Virology. 88:4493-4503 |
| ISSN: | 1098-5514 0022-538X |
| Popis: | Tegument proteins pp150 and pUL96 function at a late step in cytomegalovirus (CMV) maturation. Here, we show that pp150 interacts directly with pUL96; however, the N-terminal region of pp150 and the C-terminal region of pUL96, which are critical for these proteins to function, are not required for this interaction. Moreover, the largely dispensable C-terminal region of pp150 is critical for pp150-pUL96 interaction. To further study the role of pUL96, several point and clustered mutations were engineered into the CMV Towne bacterial artificial chromosome (Towne-BAC) genome, replacing the conserved negatively charged C-terminal residues of pUL96. Although individual point mutations (E 122 A, D 124 A, and D 125 A) reduced virus growth slightly, the clustered mutations of 122 EVDDAV 127 significantly reduced virus growth, produced small syncytial plaque phenotypes, and impacted a late stage of virus maturation. When the UL96 C-terminal alanine conversion mutant (B6-BAC) virus was serially passaged in cell culture, it gained a plaque size comparable to that of Towne-BAC, displayed an altered restriction fragment length pattern, and replicated with increased growth kinetics. Whole-genome sequencing of this passaged virus (UL96P10) and the similarly passaged Towne-BAC virus revealed major differences only in the RNA4.9 and UL96 regions. When one of the mutations in the UL96 coding region was engineered into the B6-BAC virus, it significantly increased the plaque size and rescued the virus growth rate. Thus, accumulation of compensatory mutations only in UL96 in this revertant and the specific involvement of functionally dispensable regions of pp150 in the pUL96-pp150 interaction point toward a role for pUL96 in virus maturation that does not depend upon pp150. IMPORTANCE Human cytomegalovirus causes significant medical problems in newborns, as well as in people with low immunity. In this study, we investigated the functions of two essential virus proteins, pp150 and pUL96, and determined the impact of their mutual interaction on virus replication. These studies provide valuable information that is critical for the development of targeted antiviral therapies. |
| Databáze: | OpenAIRE |
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