title: p27(SJ), a novel protein in St John's Wort, that suppresses expression of HIV-1 genome.
abstract: Transcription of the HIV-1 genome is controlled by the cooperation of viral regulatory proteins and several host factors which bind to specific DNA sequences within the viral promoter spanning the long terminal repeat, (LTR). Here, we describe the identification of a novel protein, p27(SJ), present in a laboratory callus culture of Hypericum perforatum (St John's Wort) that suppresses transcription of the HIV-1 genome in several human cell types including primary culture of microglia and astrocytes. p27(SJ) associates with C/EBPbeta, a transcription factor that regulates expression of the HIV-1 genome in macrophages and monocytic cells, and the viral transactivator, Tat. The association of p27(SJ) with C/EBPbeta and Tat alters their subcellular localization, causing their accumulation in the perinuclear cytoplasmic compartment of the cells. Fusion of a nuclear localization signal to p27(SJ) forces its entry into the nucleus and diminishes the capacity of p27(SJ) to suppress Tat activity, but does not alter its ability to suppress C/EBPbeta activation of the LTR. Results from binding assays showed the inhibitory effect of p27(SJ) on C/EBPbeta interaction with DNA. Finally, our results demonstrate that expression of p27(SJ) decreases the level of viral replication in HIV-1-infected cells. These observations suggest the potential for the development of a therapeutic advance based on p27(SJ) protein to control HIV-1 transcription and replication in cells associated with HIV-1 infection in the brain.
authors.affiliation: Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, PA, USA.
authors.forename: N
authors.initials: N
authors.lastname: Darbinian-Sarkissian
authors.forename: A
authors.initials: A
authors.lastname: Darbinyan
authors.forename: J
authors.initials: J
authors.lastname: Otte
authors.forename: S
authors.initials: S
authors.lastname: Radhakrishnan
authors.forename: B E
authors.initials: BE
authors.lastname: Sawaya
authors.forename: A
authors.initials: A
authors.lastname: Arzumanyan
authors.forename: G
authors.initials: G
authors.lastname: Chipitsyna
authors.forename: Y
authors.initials: Y
authors.lastname: Popov
authors.forename: J
authors.initials: J
authors.lastname: Rappaport
authors.forename: S
authors.initials: S
authors.lastname: Amini
authors.forename: K
authors.initials: K
authors.lastname: Khalili
mesh_terms: D001253:Astrocytes / Q000821:virology; D001483:Base Sequence; D002478:Cells, Cultured; D003864:Depression, Chemical; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D015316:Genetic Therapy / Q000379:methods*; D016679:Genome, Viral; D015658:HIV Infections / Q000188:drug therapy*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D020902:Hypericum; D017628:Microglia / Q000821:virology; D008969:Molecular Sequence Data; D008517:Phytotherapy / Q000379:methods*; D010940:Plant Proteins / Q000235:genetics / Q000627:therapeutic use*; D020079:Terminal Repeat Sequences / Q000235:genetics; D014162:Transfection / Q000379:methods; D020298:U937 Cells; D014779:Virus Replication / Q000187:drug effects
chemical_list: D010940:Plant Proteins; C510257:p27(SJ) protein, St John's Wort