Census and evaluation of p53 target genes

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• The tumor suppressor p53 (encoded by the TP53 gene) is a transcription factor crucial in preventing cancer.
• Complex models of p53 function have emerged due to the identification of numerous p53 target genes.
• TP53 gene mutations are central to many cancer types, altering p53's response pathway.

Purpose of the Study:

• To simplify and refine the understanding of p53's role as a transcription factor.
• To identify a comprehensive set of high-confidence p53 direct target genes using meta-analysis.
• To evaluate the functions of identified p53 target genes in cellular responses.

Main Methods:

• Conducted a meta-analysis of 13 high-throughput studies and individual gene analyses to identify p53 target genes.
• Compiled a total set of 3661 direct p53 target genes.
• Evaluated p53 target genes based on meta-analysis data for confidence and consistency across studies.

Main Results:

• Identified 3661 direct p53 target genes, including 3509 from high-throughput studies and 346 from individual analyses.
• Found limited consistency between p53 target genes reported in individual studies versus high-throughput studies.
• High-confidence p53 target genes are involved in diverse cellular processes: cell cycle arrest, DNA repair, apoptosis, metabolism, autophagy, mRNA translation, and feedback loops.

Conclusions:

• Many identified p53 target genes appear in few studies, suggesting a higher false-positive rate.
• p53 functions as a direct transcriptional activator; gene downregulation is indirect, requiring p21.
• Recent findings indicate a straightforward transcriptional regulation mechanism for p53.