title: Dengue virus NS4B interacts with NS3 and dissociates it from single-stranded RNA.
abstract: Dengue virus, a member of the family Flaviviridae of positive-strand RNA viruses, has seven non-structural proteins: NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5. Except for enzymic activities contained within NS3 and NS5, the roles of the other proteins in virus replication and pathogenesis are not well defined. In this study, a physical interaction between NS4B and the helicase domain of NS3 was identified by using a yeast two-hybrid assay. This interaction was further confirmed by biochemical pull-down and immunoprecipitation assays, both with purified proteins and with dengue virus-infected cell lysates. NS4B co-localized with NS3 in the perinuclear region of infected human cells. Furthermore, NS4B dissociated NS3 from single-stranded RNA and consequently enhanced the helicase activity of NS3 in an in vitro unwinding assay. These results suggest that NS4B modulates dengue virus replication via its interaction with NS3.
authors.affiliation: Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670.
authors.forename: Indira
authors.initials: I
authors.lastname: Umareddy
authors.affiliation: Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670.
authors.forename: Alex
authors.initials: A
authors.lastname: Chao
authors.affiliation: Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670.
authors.forename: Aruna
authors.initials: A
authors.lastname: Sampath
authors.affiliation: Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670.
authors.forename: Feng
authors.initials: F
authors.lastname: Gu
authors.affiliation: Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670.
authors.forename: Subhash G
authors.initials: SG
authors.lastname: Vasudevan
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003716:Dengue Virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D020365:RNA Helicases / Q000235:genetics / Q000502:physiology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000502:physiology; D013347:Subcellular Fractions / Q000821:virology; D020798:Two-Hybrid System Techniques; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000502:physiology*; D014774:Virulence; D014779:Virus Replication; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D046911:Macromolecular Substances; D020365:RNA Helicases; D012367:RNA, Viral; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C080107:NS4B protein, flavivirus