p53 binds human telomeric G-quadruplex in vitro

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• The tumor suppressor protein p53 is vital for maintaining genome stability.
• p53 is a well-characterized DNA-binding protein with diverse functions.
• Guanine quadruplexes (G-quadruplexes) are non-canonical DNA structures implicated in various cellular processes.

Purpose of the Study:

• To investigate the interaction between wild-type p53 and human telomeric G-quadruplexes.
• To determine the factors influencing p53 binding to telomeric G-quadruplexes.
• To elucidate the role of p53 DNA binding domains in G-quadruplex recognition.

Main Methods:

• Electromobility shift assay (EMSA)
• Enzyme-linked immunosorbent assay (ELISA)
• Analysis of p53 deletion mutants and selective oxidation of the p53 core domain.

Main Results:

• p53 binding to telomeric G-quadruplexes is dependent on the number of telomeric repeats.
• p53 exhibits conformational selectivity, favoring G-quadruplexes formed in potassium over those in sodium.
• The quadruplex-stabilizing ligand N-methyl mesoporphyrin IX (NMM) enhances p53 recognition of G-quadruplexes in potassium.
• Both DNA binding domains of p53 are essential for telomeric G-quadruplex recognition.

Conclusions:

• Wild-type p53 interacts with human telomeric G-quadruplexes.
• p53 displays specific binding preferences for telomeric G-quadruplex conformation and sequence length.
• The DNA binding domains of p53 play a critical role in mediating the interaction with telomeric G-quadruplexes.