CNBP controls transcription by unfolding DNA G-quadruplex structures

Area of Science:

• Molecular Biology
• Genetics
• Epigenetics

Background:

• Guanine-rich DNA can form G-quadruplex (G4) structures.
• G4-DNA at transcription start sites influences gene expression.
• Proteins regulating G4 structures are key to transcriptional control.

Purpose of the Study:

• To investigate CNBP's role as a G4-unfolding protein.
• To determine CNBP's effect on oncogene and developmental gene transcription.
• To elucidate CNBP's mechanism in G4-mediated gene regulation.

Main Methods:

• In vitro G4 unfolding assays using TG4T oligonucleotide and oncogene promoter G4s.
• Cellular experiments involving CNBP depletion to assess KRAS transcription.
• In vitro and in vivo (zebrafish) studies on CNBP's effect on NOG G4 and NOGGIN transcription.

Main Results:

• CNBP demonstrated in vitro G4-unfolding activity on various G4 structures.
• CNBP depletion reduced endogenous KRAS transcription, indicating a relieving role.
• CNBP repressed NOGGIN transcription via G4 unwinding in cellular and zebrafish models.

Conclusions:

• CNBP functions as a G4-unfolding protein influencing gene transcription.
• CNBP's activity impacts both oncogene (KRAS) and developmental gene (NOGGIN) expression.
• G-quadruplexes are functional regulatory elements in living organisms, modulated by proteins like CNBP.