Telomere

Telomeres are repetitive stretches of DNA and proteins found at the ends of all chromosomes, from worms to humans, whose main function is to protect a cell’s nuclear material from damage. With each cell division, telomeres become progressively shorter, limiting the number of times a cell can divide. When the length of telomeres reaches a critically short length, the cells stop dividing and enter a state of cell arrest (i.e., senescence), which is one of the hallmarks of aging. The length of telomeres can be maintained by an enzyme, telomerase, which adds DNA bases to the end of chromosomes. Most cells, however, lack sufficient telomerase, and as a consequence, their telomeres become shorter over time. Some cells, such as stem cells, can maintain the ability ...