title: Novel function of the poly(c)-binding protein α-CP2 as a transcriptional activator that binds to single-stranded DNA sequences.
abstract: α-complex protein 2 (α-CP2) is known as an RNA-binding protein that interacts in a sequence-specific manner with single-stranded polycytosine [poly(C)]. This protein is involved in various post-transcriptional regulations, such as mRNA stabilization and translational regulation. In this study, the full-length mouse α-CP2 gene was expressed in an insoluble form with an N-terminal histidine tag in Escherichia coli and purified for homogeneity using affinity column chromatography. Its identity was confirmed using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Recombinant α-CP2 was expressed and refolded. The protein folding conditions for denatured α-CP2 were optimized. DNA and RNA electrophoretic mobility shift assays demonstrated that the recombinant α-CP2 is capable of binding to both single-stranded DNA and RNA poly(C) sequences. Furthermore, plasmids expressing α-CP2 activated the expression of a luciferase reporter when co-transfected with a single-stranded (pGL-SS) construct containing a poly(C) sequence. To our knowledge, this study demonstrates for the first time that α-CP2 functions as a transcriptional activator by binding to a single-stranded poly(C) sequence.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Ewha Medical Research Institute, Ewha Womans University School of Medicine, Yangcheon‑gu, Seoul 158-710, Republic of Korea.
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Kang
authors.forename: Kyu Young
authors.initials: KY
authors.lastname: Song
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Wei
authors.forename: Ping-Yee
authors.initials: PY
authors.lastname: Law
authors.forename: Horace H
authors.initials: HH
authors.lastname: Loh
authors.forename: Hack Sun
authors.initials: HS
authors.lastname: Choi
mesh_terms: D000818:Animals; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D051379:Mice; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics / Q000502:physiology
chemical_list: D004277:DNA, Single-Stranded; D016601:RNA-Binding Proteins
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