title: Quantification of the HIV transcriptional activator complex in live cells by image-based protein-protein interaction analysis.
abstract: The virus-encoded Tat protein is essential for HIV transcription in infected cells. The interaction of Tat with the cellular transcription elongation factor P-TEFb (positive transcriptional elongation factor b) containing cyclin T1 (CycT1) and cyclin-dependent kinase 9 (CDK9) is critical for its activity. In this study, we use the Fluoppi (fluorescent-based technology detecting protein-protein interaction) system, which enables the quantification of interactions between biomolecules, such as proteins, in live cells. Quantitative measurement of the molecular interactions among Tat, CycT1 and CDK9 has showed that any third molecule enhances the binding between the other two molecules. These findings suggest that each component of the Tat:P-TEFb complex stabilizes the overall complex, thereby supporting the efficient transcriptional elongation during viral RNA synthesis. These interactions may serve as appropriate targets for novel anti-HIV therapy.
authors.affiliation: Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Asamitsu
authors.affiliation: Department of Virology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Omagari
authors.affiliation: Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Okuda
authors.affiliation: Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan.
authors.forename: Yurina
authors.initials: Y
authors.lastname: Hibi
authors.affiliation: Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Okamoto
mesh_terms: D056906:Cyclin T / Q000235:genetics* / Q000378:metabolism; D042863:Cyclin-Dependent Kinase 9 / Q000235:genetics* / Q000378:metabolism; D006678:HIV / Q000235:genetics* / Q000472:pathogenicity; D015658:HIV Infections / Q000235:genetics / Q000821:virology; D006801:Humans; D046912:Multiprotein Complexes / Q000235:genetics; D042925:Positive Transcriptional Elongation Factor B / Q000235:genetics* / Q000378:metabolism; D060066:Protein Interaction Maps / Q000235:genetics; D014158:Transcription, Genetic; D014779:Virus Replication / Q000235:genetics; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics* / Q000378:metabolism
chemical_list: C503684:CCNT1 protein, human; D056906:Cyclin T; D046912:Multiprotein Complexes; D054322:tat Gene Products, Human Immunodeficiency Virus; D042925:Positive Transcriptional Elongation Factor B; C467969:CDK9 protein, human; D042863:Cyclin-Dependent Kinase 9