Wild-type p53 binds to MYC promoter G-quadruplex

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• G-quadruplexes are non-canonical DNA structures involved in gene regulation.
• The tumor suppressor p53 protein regulates crucial cellular processes.
• p53 is known to interact with various DNA structures beyond canonical sequences.

Purpose of the Study:

• To investigate the binding of wild-type p53 (wtp53) to a G-quadruplex structure in the MYC gene promoter.
• To determine if p53's C-terminal region is involved in G-quadruplex binding.
• To assess p53-G-quadruplex interaction in cellular contexts.

Main Methods:

• Electrophoretic mobility shift assays (EMSAs) to study protein-DNA interactions.
• Analysis of p53 binding to a specific G-quadruplex motif in the MYC promoter.
• Investigation of p53 binding in cell lines expressing wtp53.

Main Results:

• Wtp53 exhibits high-affinity binding to the MYC promoter G-quadruplex, comparable to its binding to a consensus p53 DNA sequence.
• The C-terminal region of p53 (aa 320-393) is sufficient for high-affinity binding to the MYC G-quadruplex.
• Wtp53 was observed to bind the MYC promoter G-quadruplex region within cells expressing wtp53.

Conclusions:

• Wtp53 directly interacts with G-quadruplex structures, specifically within the MYC promoter.
• The C-terminal domain of p53 plays a significant role in mediating G-quadruplex binding.
• These findings suggest a novel mechanism for p53-mediated transcriptional regulation involving G-quadruplex DNA structures.