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Biochim Biophys Acta. 2013 Oct;1830(10):4769-77. doi: 10.1016/j.bbagen.2013.06.007. Epub 2013 Jun 14.

Mechanistic studies for the role of cellular nucleic-acid-binding protein (CNBP) in regulation of c-myc transcription.

Author information

1
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou University City, Guangzhou, People's Republic of China.

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.

GENERAL SIGNIFICANCE:

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.

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

PMID:
23774591
DOI:
10.1016/j.bbagen.2013.06.007
[Indexed for MEDLINE]

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