title: Mutations in the DI-DII Linker of Human Parainfluenza Virus Type 3 Fusion Protein Result in Diminished Fusion Activity.
abstract: Human parainfluenza virus type 3 (HPIV3) can cause severe respiratory tract diseases in infants and young children, but no licensed vaccines or antiviral agents are currently available for treatment. Fusing the viral and target cell membranes is a prerequisite for its entry into host cells and is directly mediated by the fusion (F) protein. Although several domains of F are known to have important effects on regulating the membrane fusion activity, the roles of the DI-DII linker (residues 369-374) of the HPIV3 F protein in the fusogenicity still remains ill-defined. To facilitate our understanding of the role of this domain might play in F-induced cell-cell fusion, nine single mutations were engineered into this domain by site-directed mutagenesis. A vaccinia virus-T7 RNA polymerase transient expression system was employed to express the wild-type or mutated F proteins. These mutants were analyzed for membrane fusion activity, cell surface expression, and interaction between F and HN protein. Each of the mutated F proteins in this domain has a cell surface expression level similar to that of wild-type F. All of them resulted in a significant reduction in fusogenic activity in all steps of membrane fusion. Furthermore, all these fusion-deficient mutants reduced the amount of the HN-F complexes at the cell surface. Together, the results of our work suggest that this region has an important effect on the fusogenic activity of F.
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China.
authors: Wenyan
authors: W
authors: Xie
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China.
authors: Hongling
authors: H
authors: Wen
authors: Department of Laboratory Medicine, Provincial Hospital affiliated to Shandong University, Jinan, China.
authors: Fulu
authors: F
authors: Chu
authors: Department of Neurosurgery, Qilu Hospital of Shandong University, Jinan, China.
authors: Shaofeng
authors: S
authors: Yan
authors: Shandong Center for Disease Control and Prevention, Jinan, China.
authors: Bin
authors: B
authors: Lin
authors: Department of Laboratory Medicine, Shandong Tumor Hospital and Institute, Jinan, China.
authors: Wenli
authors: W
authors: Xie
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China.
authors: Ying
authors: Y
authors: Liu
authors: Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China.
authors: Guijie
authors: G
authors: Ren
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China.
authors: Li
authors: L
authors: Zhao
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China.
authors: Yanyan
authors: Y
authors: Song
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China.
authors: Chengxi
authors: C
authors: Sun
authors: Department of Virology, School of Public Health, Shandong University, Jinan, China; The Key Laboratory for Experimental Teratology of the Ministry of Education, Shandong University, Jinan, China.
authors: Zhiyu
authors: Z
authors: Wang
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D015726:Giant Cells / Q000378:metabolism; D015707:HN Protein / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D007700:Kinetics; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D016296:Mutagenesis; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010224:Parainfluenza Virus 3, Human / Q000235:genetics*; D011485:Protein Binding; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000235:genetics*
chemical_list: D000596:Amino Acids; D015707:HN Protein; D050505:Mutant Proteins; D014760:Viral Fusion Proteins; C072983:F protein, parainfluenza virus 3