p53 coordinates base excision repair to prevent genomic instability.

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• DNA damage is continuously generated by mutagens.
• The Base Excision Repair (BER) pathway repairs most DNA lesions.
• Unrepaired DNA single-strand breaks (SSBs) can lead to genomic instability.

Purpose of the Study:

• To elucidate the regulatory mechanisms of the BER pathway.
• To investigate the role of p53 in coordinating BER.
• To understand how BER dysfunction contributes to genomic instability.

Main Methods:

• Investigated the impact of unrepaired SSBs on BER components.
• Utilized p53 functional assays and APE1 endonuclease activity measurements.
• Analyzed DNA strand break accumulation and genomic instability markers.

Main Results:

• Accumulation of unrepaired SSBs induces p53/Sp1-dependent downregulation of APE1.
• Impaired p53 function results in APE1 overexpression and increased DNA strand breaks.
• p53 dysfunction leads to genomic instability due to failed BER coordination.

Conclusions:

• p53 plays a critical, previously unrecognized role in coordinating BER.
• Dysfunction of this p53-mediated BER coordination mechanism contributes to genomic instability in p53-inactivated cells, common in cancer.