Senescence and immortalization: role of telomeres and telomerase

Telomeres and Telomerase in Cellular Aging (Senescence)

Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence [7] or cellular aging [8]. Integral to this process is telomerase, which is an enzyme that repairs telomeres and is present i...

Role of telomeres and telomerase in cancer.

There is mounting evidence for the existence of an important relationship between telomeres and telomerase and cellular aging and cancer. Normal human cells progressively lose telomeres with each cell division until a few short telomeres become uncapped leading to a growth arrest known as replicative aging. In the absence of genomic alterations these cells do not die but remain quiescent produc...

Telomeres and telomerase.

Telomeres are the protective DNA-protein complexes found at the ends of eukaryotic chromosomes. Telomeric DNA consists of tandem repeats of a simple, often G-rich, sequence specified by the action of telomerase, and complete replication of telomeric DNA requires telomerase. Telomerase is a specialized cellular ribonucleoprotein reverse transcriptase. By copying a short template sequence within ...

SnapShot: Telomeres and Telomerase

The role of senescence and immortalization in carcinogenesis.

Normal somatic cells are able to divide only a limited number of times before they become senescent. The occurrence of intratumoral cell death and the need for clonal evolution mean that many more cell divisions are required for tumorigenesis than is possible unless cells breach the senescence proliferation barrier and become immortalized. Senescence may therefore be a major tumor suppressor me...