P Licciardo1, G Napolitano, B Majello, L Lania. 1. Department of Genetics, Molecular and General Biology, University of Naples Federico II and the International Institute of Genetics and Biophysics, Italy.
Abstract
OBJECTIVES: To asses the role of the RNAPII carboxy-terminal domain (CTD) phosphatase FCP1 on HIV-1 Tat-mediated transactivation. DESIGN: Construction of expression vectors encoding FCP1 phosphatase and analysis of their functions on Tat activity. METHODS: Basal and Tat-mediated transactivation of HIV-1 long terminal repeat (LTR)-driven transcription was compared, by transient transfections, in the presence of FCP1 phosphatase. Protein interactions were analysed by in vitro binding assays. RESULTS: FCP1 specifically and effectively represses Tat transactivation but not HIV-1 LTR-basal transcription. Protein interaction assays demonstrated that FCP1 specifically and directly binds Tat in vitro. CONCLUSION: The specific and efficient inhibitory function of FCP1 highlights the important role of this CTD-phosphatase in Tat-mediated transactivation, and it suggests that FCP1 might represent a specific target for modulation of Tat activity in infected cells.
OBJECTIVES: To asses the role of the RNAPII carboxy-terminal domain (CTD) phosphatase FCP1 on HIV-1Tat-mediated transactivation. DESIGN: Construction of expression vectors encoding FCP1 phosphatase and analysis of their functions on Tat activity. METHODS: Basal and Tat-mediated transactivation of HIV-1 long terminal repeat (LTR)-driven transcription was compared, by transient transfections, in the presence of FCP1 phosphatase. Protein interactions were analysed by in vitro binding assays. RESULTS:FCP1 specifically and effectively represses Tat transactivation but not HIV-1 LTR-basal transcription. Protein interaction assays demonstrated that FCP1 specifically and directly binds Tat in vitro. CONCLUSION: The specific and efficient inhibitory function of FCP1 highlights the important role of this CTD-phosphatase in Tat-mediated transactivation, and it suggests that FCP1 might represent a specific target for modulation of Tat activity in infected cells.
Authors: Liming Xiong; Hojoung Lee; Manabu Ishitani; Yuko Tanaka; Becky Stevenson; Hisashi Koiwa; Ray A Bressan; Paul M Hasegawa; Jian-Kang Zhu Journal: Proc Natl Acad Sci U S A Date: 2002-07-29 Impact factor: 11.205