title: Residues R(199)H(200) of prototype foamy virus transactivator Bel1 contribute to its binding with LTR and IP promoters but not its nuclear localization.
abstract: Prototype foamy virus encodes a transactivator called Bel1 that enhances viral gene transcription and is essential for PFV replication. Nuclear localization of Bel1 has been reported to rely on two proximal basic motifs R(199)H(200) and R(221)R(222)R(223) that likely function together as a bipartite nuclear localization signal. In this study, we report that mutating R(221)R(222)R(223), but not R(199)H(200), relocates Bel1 from the nucleus to the cytoplasm, suggesting an essential role for R(221)R(222)R(223) in the nuclear localization of Bel1. Although not affecting the nuclear localization of Bel1, mutating R(199)H(200) disables Bel1 from transactivating PFV promoters. Results of EMSA reveal that the R(199)H(200) residues are vital for the binding of Bel1 to viral promoter DNA. Moreover, mutating R(199)H(200) in Bel1 impairs PFV replication to a much greater extent than mutating R(221)R(222)R(223). Collectively, our findings suggest that R(199)H(200) directly participate in Bel1 binding to viral promoter DNA and are indispensible for Bel1 transactivation activity.
authors.affiliation: Key Laboratory of Molecular Microbiology and Biotechnology (Ministry of Education) and Key Laboratory of Microbial Functional Genomics (Tianjin), College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Ma
authors.affiliation: Key Laboratory of Molecular Microbiology and Biotechnology (Ministry of Education) and Key Laboratory of Microbial Functional Genomics (Tianjin), College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Tan
authors.affiliation: Key Laboratory of Molecular Microbiology and Biotechnology (Ministry of Education) and Key Laboratory of Microbial Functional Genomics (Tianjin), College of Life Sciences, Nankai University, Tianjin 300071, China; Centre Laboratory, TianJin 4th Centre Hospital, Tianjin 300140, China.
authors.forename: Xiaoxu
authors.initials: X
authors.lastname: Cui
authors.affiliation: Key Laboratory of Molecular Microbiology and Biotechnology (Ministry of Education) and Key Laboratory of Microbial Functional Genomics (Tianjin), College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Di
authors.initials: D
authors.lastname: Luo
authors.affiliation: Key Laboratory of Molecular Microbiology and Biotechnology (Ministry of Education) and Key Laboratory of Microbial Functional Genomics (Tianjin), College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada H3T 1E2; Departments of Medicine McGill University, Montreal, QC, Canada; Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Chen
authors.initials: C
authors.lastname: Liang
authors.affiliation: Key Laboratory of Molecular Microbiology and Biotechnology (Ministry of Education) and Key Laboratory of Microbial Functional Genomics (Tianjin), College of Life Sciences, Nankai University, Tianjin 300071, China. Electronic address: wentaoqiao@nankai.edu.cn.
authors.forename: Wentao
authors.initials: W
authors.lastname: Qiao
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000821:virology*; D015967:Gene Expression Regulation, Viral; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D021381:Protein Transport; D012192:Retroviridae Infections / Q000821:virology*; D012191:Retroviridae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016092:Spumavirus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020079:Terminal Repeat Sequences; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D012191:Retroviridae Proteins; D015534:Trans-Activators; C074061:bel1 protein, Human foamy virus
keywords: Bel1; Internal promoter (IP); Long terminal repeat (LTR); Nuclear localization signal (NLS); Transactivation