Abstract
Continuous inhibition of tumor suppressor protein P53 can cause unlimited cell proliferation, which indicates that P53 may be a major factor in regulating cell senescence. The decrease of copy number of telomere DNA and ribosomal DNA (rDNA) can inhibit the degradation of P53 protein. Therefore, with the decrease of copy number of telomere DNA and rDNA in chromosome, the concentration of P53 protein in cells will be higher and higher, which will make cells aging. Telomere DNA and rDNA may lose their own copies in the process of transcription, replication or damage repair. Therefore, factors or conditions that silence telomere DNA and rDNA can prolong cell life.