title: Mechanistic studies for the role of cellular nucleic-acid-binding protein (CNBP) in regulation of c-myc transcription.
abstract: BACKGROUND
  Guanine-rich sequence of c-myc nuclease hypersensitive element (NHE) III1 is known to fold in G-quadruplex and subsequently serves as a transcriptional silencer. Cellular nucleic-acid-binding protein (CNBP), a highly conserved zinc-finger protein with multiple biological functions, could bind to c-myc NHE III1 region, specifically to the single strand G-rich sequence.
  
  
  METHODS
  In the present study, a variety of methods, including cloning, expression and purification of protein, EMSA, CD, FRET, Ch-IP, RNA interference, luciferase reporter assay, SPR, co-immunoprecipitation, and co-transfection, were applied to investigate the mechanism for the role of CNBP in regulating c-myc transcription.
  
  
  RESULTS
  We found that human CNBP specifically bound to the G-rich sequence of c-myc NHE III1 region both in vitro and in cellulo, and subsequently promoted the formation of G-quadruplex. CNBP could induce a transient decrease followed by an increase in c-myc transcription in vivo. The interaction of CNBP with NM23-H2 was responsible for the increase of c-myc transcription.
  
  
  CONCLUSIONS
  Based on above experimental results, a new mechanism, involving G-quadruplex related CNBP/NM23-H2 interaction, for the regulation of c-myc transcription was proposed.
  
  
  CONCLUSIONS
  These findings indicated that the regulation of c-myc transcription through NHE III1 region might be governed by mechanisms involving complex protein-protein interactions, and suggested a new possibility of CNBP as a potential anti-cancer target based on CNBP's biological function in c-myc transcription.
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou University City, Guangzhou, People's Republic of China.
authors.forename: Siqi
authors.initials: S
authors.lastname: Chen
authors.forename: Lijuan
authors.initials: L
authors.lastname: Su
authors.forename: Jun
authors.initials: J
authors.lastname: Qiu
authors.forename: Nannan
authors.initials: N
authors.lastname: Xiao
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.forename: Jia-Heng
authors.initials: JH
authors.lastname: Tan
authors.forename: Tian-Miao
authors.initials: TM
authors.lastname: Ou
authors.forename: Lian-Quan
authors.initials: LQ
authors.lastname: Gu
authors.forename: Zhi-Shu
authors.initials: ZS
authors.lastname: Huang
authors.forename: Ding
authors.initials: D
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D047369:Chromatin Immunoprecipitation; D002942:Circular Dichroism; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D031541:Fluorescence Resonance Energy Transfer; D016259:Genes, myc; D006801:Humans; D008969:Molecular Sequence Data; D054778:NM23 Nucleoside Diphosphate Kinases / Q000378:metabolism; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: C433227:CNBP protein, human; D017931:DNA Primers; D054778:NM23 Nucleoside Diphosphate Kinases; D016601:RNA-Binding Proteins; C517940:NME2 protein, human
keywords: 6-carboxyfluorescein; CD; CNBP; Cellular nucleic-acid-binding protein; ChIP; Co-IP; EMSA; FAM; FRET; G-quadruplex; NHE; Nuclease hypersensitive element III(1); RT-qPCR; SPR; TAMRA; TMPyP4; Transcriptional regulation; c-myc; cellular nucleic-acid-binding protein; chromatin immunoprecipitation; circular dichroism; co-immunoprecipitation; electrophoretic mobility shift assay; fluorescence resonance energy transfer; meso-tetra(N-methyl-4-pyridyl)porphine; nuclease hypersensitive element; reverse transcription-quantitative polymerase chain reaction; surface plasmon resonance; tetramethylrhodamine