title: Novel dual-binding function of a poly (C)-binding protein 3, transcriptional factor which binds the double-strand and single-stranded DNA sequence.
abstract: Poly(C)-binding proteins (PCBPs) are generally known as RNA-binding proteins that interact in a sequence-specific manner with single-stranded poly(C) sequences. These proteins are mainly involved in various posttranscriptional regulations (e.g., mRNA stabilization or translational activation/silencing). This study reports a novel dual-binding function for PCBP3, a member of the PCBP family. Recombinant PCBP3 was purified using affinity column chromatography and its identity confirmed by MALDI-TOF mass spectrometry. The protein folding conditions of the purified and renatured PCBP3 were optimized. Electrophoretic mobility shift assays demonstrated that the recombinant PCBP3 is capable of binding to both double- and single-strand poly(C) sequences. Furthermore, plasmids expressing PCBP3 repressed the expression of luciferase reporters when cotransfected with single-strand (pGL-SS) and double-strand (pGL-DS) constructs containing poly(C) sequences in their promoters. This study demonstrates for the first time that PCBP3 can function as a repressor dependent on binding to single-strand and double-stranded poly(C) sequences.
authors.affiliation: Division of Nephrology Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul 158-710, South Korea.
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Kang
authors.forename: Kyu Young
authors.initials: KY
authors.lastname: Song
authors.forename: Hack Sun
authors.initials: HS
authors.lastname: Choi
authors.forename: Ping-Yee
authors.initials: PY
authors.lastname: Law
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Wei
authors.forename: Horace H
authors.initials: HH
authors.lastname: Loh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002846:Chromatography, Affinity; D004247:DNA / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D051379:Mice; D008969:Molecular Sequence Data; D011066:Poly C / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C525095:Pcbp3 protein, mouse; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D011066:Poly C; D004247:DNA