Thread: cells NOT effected by telomerase

I'm working on homework for my cancer biology course, and I cannot seem to find any information in the reading that points to an answer for one question:

What types of cells does telomerase not have an effect on?

Hi Sayyadina,

Possibly mammalian erythrocytes (red blood cells) will be unaffected by telomerase, as individual erythrocytes lose their nucleus during development, to become anucleate. They therefore lack a nucleus and, presumably, lack DNA and its associated telomeres thus telomerase will have no effect.

Best wishes,

Tri~

Also not sure what effect it would have on gametes or nerve cells?

Gametes are not affected by telomerase.

It would have an effect on all cells that undergo mitosis. Each round of mitosis shortens the telomere; telomerase elongates it again. However, telomerase synthesis is switched off in all body cells. Body cells have a finite number of times they can replicate (the Hayflick limit). After a given number of replications, the telomere is so worn down that another round of mitosis would effect coding DNA. For example, if you take fibroblasts from a young specimen and grow them in culture, they'll replicate more times than cells taken from an older specimen, as the telomeres are already shortened to an extent. As such, the induction of telomerase production in normal tissue can cause tumour formation.

Stem cells (during embryogenesis) and immune cells (when triggered by an infection) express telomerase, but lack of regulation in normal tissue cells is ultimately detrimental.

Originally Posted by KALSTER

Also not sure what effect it would have on gametes or nerve cells?

Nerve cells never replicate. Throughout a lifetime, a complex neural web is formed, one which could not easily be replaced by a new cell without having an effect on memory or personality. It's thought that this is why the maximal life span of humans (115-120 years old) is because of nerve cells senescence. No matter how long we try to prolong it, we'll never outlive our nervous system.

Gametes aren't affected because they don't undergo mitosis so there's no need for it.


In short, the substrate for telomerase is a telomere that has just been shortened by DNA replication. Any cell in which it is expressed will be 'effected' by it.