P53 gene

p53 (also known as protein 53 or tumor protein 53) is a gene that in humans is encoded by the TP53 gene. It is crucial in multicellular organisms, where it regulates the cell cycle and thus functions as a tumor suppressor that is involved in preventing cancer. As such, p53 has been described as "the guardian of the genome" because of its role in conserving stability by preventing genome mutation.

Structure

The TP53 gene is located on the short arm of chromosome 17 (17p13.1). The gene spans 20 kb, with a non-coding exon 1 and a coding region that is spread over 11 exons. The coding region (exons 2-11) encodes a protein of 393 amino acids. The p53 protein is a transcription factor that is activated in response to various stress signals, including DNA damage, oxidative stress, and activated oncogenes.

Function

The p53 protein regulates the cell cycle and functions as a tumor suppressor. It has many mechanisms of anti-cancer function, and plays a role in apoptosis, genetic stability, and inhibition of angiogenesis. In its anti-cancer role, p53 works through several mechanisms:

• It can activate DNA repair proteins when DNA has sustained damage.
• It can induce growth arrest by holding the cell cycle at the G1/S regulation point on DNA damage recognition.
• It can initiate apoptosis, the programmed cell death, if the DNA damage proves to be irreparable.

Clinical significance

Mutations in the TP53 gene can lead to Li-Fraumeni syndrome, a rare, inherited disorder that greatly increases the risk of developing several types of cancer, particularly in young adults and children. Some mutations can also lead to cancers of the breast, ovary, bladder, colon, lung, liver, and pancreas.

See also

• Mdm2
• p63
• p73
• p21
• Cancer
• Tumor suppressor

References

P53 gene Resources
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