title: Induction of MHC Class I HLA-A2 promoter by dengue virus occurs at the NFκB binding domains of the Class I Regulatory Complex.
abstract: Despite aggressive efforts in dengue research, the control of dengue diseases and discovery of therapeutics against them await complete elucidation of its complex immune-pathogenesis. Unlike many viruses that escape the host's immune responses by suppressing the major histocompatibility complex (MHC) Class I pathway, many Flaviviruses up-regulate the cell surface expression of MHC Class I complex. We recently reported MHC Class I HLA-A2 promoter activation by all serotypes of dengue virus (DV). The mechanism by which DV regulates this is further explored here in HepG2 human liver cell line. Using real-time PCR, evidence that, similar to infections by other Flaviviruses, DV infection has the ability to up-regulate the MHC Class I transcription and mRNA synthesis, is presented. The region responsive towards DV infection of all serotypes was mapped to the Class I Regulatory Complex (CRC) of the HLA-A2 promoter. Competition electrophoretic mobility shift assay (EMSA) with NFκB probe established the presence of specific DNA-protein complex in DV-infected nuclear extracts. Antibody-supershift assays identified the MHC Class I promoter activation by DV to occur through binding of p65/p50 heterodimers and p65 homodimers to κB1 and κB2 cis-acting elements, respectively, within the CRC, and not with the interferon consensus sequence (ICS). This study presents evidence of MHC Class I gene modulation by DV, hence providing a better understanding of dengue immune-pathogenesis that would consequently facilitate the discovery of antiviral therapeutics against dengue.
authors: Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. shatraho@um.edu.my
authors: Shatrah
authors: S
authors: Othman
authors: Noorsaadah Abd
authors: NA
authors: Rahman
authors: Rohana
authors: R
authors: Yusof
mesh_terms: D004247:DNA / Q000378:metabolism; D003716:Dengue Virus / Q000276:immunology*; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D015789:HLA-A2 Antigen / Q000096:biosynthesis* / Q000235:genetics; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000276:immunology / Q000821:virology; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D060888:Real-Time Polymerase Chain Reaction; D015533:Transcriptional Activation
chemical_list: D015789:HLA-A2 Antigen; D016328:NF-kappa B; D004247:DNA