What gene is responsible for limiting the cell's ability to replicating and regenerating?
Jul 29, 2010 in
Anti Aging FAQs
Could you explain the limitating mechanism of cellular replication please? I’m really interested in anti aging medicine and i’ve read that one of the biggest obstacle of AAM is the cell’s mechanism to limiting it’s replication and regeneration……
So is there anyway to avoid the Hayflick limit in progeny cells without injecting extra telomerase into cells (which is currently impossible to do and risky)
WOW great answer James and Daemon…. thanks! yaaaayyyy!
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4 comments
James B, Researcher at UNC-CH on July 29, 2010 at 2:47 pm
As with most science questions, it’s usually never as simple as one answer such as "a gene". Many factors limit the ability of a cell to replicate. Such factors include availability of nutrients (genes that produce growth factors), necessity of that particular cell type (too many of a certain type of cell or not enough), and what I believe to be a critical answer to your question: the role of telomeres.
In each cell, DNA exists. DNA is also replicated each time the cell divides to form two daughter cells. A consequence of cell division is the shorting of DNA each time cells divide. Scientists have shown that when old, we possess shorter DNA than when we were younger and that this shortening will reach actual genes if you live long enough. To counteract this process of shortening, DNA possesses non-coding (at least we think non-coding) telomeres at the ends of each strand. Scientists believe that these telomeres act as caps that serve as protection to genes. Therefore, during each replication, telomeres shorten instead of genes being erased.
Until we can find a method to counter act telomere shortening (perhaps with telomerase, an enzyme that produces telomeres), cells will continue to age and be replaced (not necessarily a bad thing, e.g. cancer).
***In re to your second question, there are a few ways to make cells avoid the limit to division. Scientists call this process, immortalization. It can be performed by transfecting viral genes (usually Epstein Barr) into a human cell. The other, as mentioned above telomerase expression. A doctor and one of the students in my lab performs this immortalization process on B cells so that we can study these cells in tissue culture for longer periods of time. However, the processes of immortalization take place after the cells have been removed from our patients.
What is interesting is that stem cells can survive for a very long time (if not the entire life of the organism) by using telomerase and probably other factors. But understand that these cells do not possess the same phenotype or physical and chemical "image" as their differentiated counterparts. In other words, stem cells most likely have many other factors other than telomerase that keep them from dying after a certain number of divisions (contact-dependent signalling with other cells; paracrine factors such as growth factors, etc.). It will be interesting to see what pops up in journals in the months and years ahead.***
blessy on July 29, 2010 at 2:47 pm
google search is best,
all the best
dameon1532 on July 29, 2010 at 2:47 pm
There is no "gene" that limits a cell’s ability to replicate. The cell’s DNA contains something called a telomere. The telomere is the end of the DNA sequence. It is a repeating sequence. This sequence slowly gets degraded as the cell replicates, and eventually all but dissappears. At this point, the cell no longer replicates, as the DNA would be degraded too much and subsequent cells would lose vital information. However, there is an enzyme that very few cells make. This enzyme, known as telomerase, can rebuild the telomere, basically making the cell "immortal". This is actually something that cancer research has been looking into. It is quite interesting. Do some more research on that… try medline.
Pocket Protectorate on July 29, 2010 at 2:47 pm
Well…
We know that too much sunlight "ages" our skin prematurely, and we know certain other "lifestyle" abuses can prematurely age people…(you should see those "before and after" photos of people who abused meth too much, and so…
We also know that the "vibration" of walking and jogging stimulates new "bone growth" in senior citizens, and when they were forced to walk every day and do puzzles and such, they were able to recover some lost brain functions and become more cognizant, so…
We know that dry skin is probably an aging thing, too…
And we certainly know that "marriage & children" is an aging thing (you should see my poor friends (whew! while I look like I’m 25, and you know why? You wanna know the secret of staying young looking?
Well…Here’s the secret to staying young forever…all you have to do is…
("Thunk!")
(Suddenly an arrow sprouts from my bloody chest, and I slump down in my computer chair dead from old age…)