Telomeres are the very end of linear DNA that is always repetitive. Although it belongs to a strand of DNA, telomeres do not encode any proteins, so they do not fall into the gene category. Telomeres play an important role in maintaining the genome stability of each cell. With telomeres, DNA multiplier that takes place before cell division can be done completely.
Telomeres are present mainly in eukaryotic cells, because the DNA of prokaryotic cells forms circular chains, therefore it has no termination sites, although there are exceptions such as bacteria with linear DNA and those that have telomeres.
Each time a cell divides, telomeres are slightly shortened, as the main enzyme participating in semiconservative DNA replication – polymerase DNA – requires anchoring 16 repetitions of the TTAGGG sequence (in human case) and only copying genetic material afterwards, leading to the final shortening of DNA molecules.
Since these do not regenerate, it reaches the point where they no longer allow proper chromosomal replication and the cell loses its ability to split completely or partially, because polymerase DNA is unable to replicate genetic material.
Shortening telomeres can also eliminate certain genes that are indispensable for cell survival or silence nearby genes. Since the cell renewal process does not tolerate cell death before proper cell division, organisms tend to die within a short period of time when their telomeres run out.
The history of telomere
Telomeres were first discovered by Elizabeth Blackburn at Yale University with Joseph Gall and published in 1978. Later in the 2009, Elizabeth Blackburn, Carol Greider, and Jack Szostak won the Nobel prize in medicine in his discovery of how telomeres and telomerase could keep chromosomes.
William Henry “Bill” Andrews, Ph.D. and his team at Geron Corporation were the first to identify human telomerase. He is also able to multiply telomerase and strives to explore how to be youthful by increasing the amount of telomerase. Andrew eventually looked for molecules that could bind to the repressive side of telomerase to make telomerase performance work to the maximum.
In 1999, Andrew finally founded his own company called Sierra Sciences and continued his research to continue to look for telomerase repressors. In 2008, he used the C0057684 gene and screened 4,000 chemicals per week to find a formula for telomeres to survive.
Finally, the wait ended in 2010 when Andrew met John Anderson, a master of nutritional product formulas for which more than 2300 products have been created. A year later they finally managed to find the right formula to protect and maintain telomeres and telomerase known as Product B, telomere-supporting nutraceutical. This product contains 1,000 patented natural ingredients.
In most organisms, telomeres are formed by simple nucleotide repetition. It is important that telomeres are associated with proteins or special settings so that they can be distinguished from chromosomal damage.
In humans, telomeres are formed by the repetition of six nucleotides: TTAGGG, which consists of tens of kilobases. Human telomeres also contain a small patch of a single strand with several hundred nucleotides.
At least half of mammalian chromosomes are believed to have telomeres that form a more complex type of arrangement, called T-loops. This T-loop has between five and ten thousand bases of DNA and it is catalyzed by the TRF2 protein, which helps stabilize the chromosome tip. In addition to the presence of TRF2, the formation of T-loops also depends on two more factors: double tape repetition and single tape repetition.
Telomeres are synthesized at the end of DNA replication by the telomerase enzyme, which is reverse transcriptase, as it synthesizes DNA using RNA molecules as a template.
What is the function of telomeres?
Telomeres serve three main purposes:
- They helped organize each of our 46 chromosomes inside the nucleus (control center) of our cell.
- They protect the ends of our chromosomes by forming a cap, such as plastic tips on shoelaces. If telomeres aren’t there, our chromosomes may end up sticking to other chromosomes.
- They allow chromosomes to be replicated correctly during cell division:
Every time a cell does DNA replication, Chromosomes are abbreviated to approximately 25-200 bases (A, C, G, or T) per replication.
However, since the tip is protected by telomeres, the only part of the chromosome that is missing, is the telomeres, and the DNA is left damaged.
Without telomeres, important DNA will disappear every time a cell divides (usually about 50 to 70 times).
This will ultimately lead to the loss of the entire gene.
Thank you very much for reading Telomere Definition, History, Structure, and Functions, hopefully useful.
- Image: AJC1, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons.
- Video: Joe Fullerton,