What is telomere?

We all know our chronological age - the one the passport talks about. But at the same time, we notice that not everyone looks their own years - someone younger and someone older. Here it is already a matter of the biological age, which certainly cannot be determined by the date of birth. He speaks not only about external freshness, but also about the " youth " of our organs, vital systems, cells. Biological age is evidence of our rational (or vice versa ) use of the genetic program. But it is “ recorded ” in the telomeres of the cell, about which we have to learn a lot of interesting things today.

What is telomere?

The word came from a combination of others - Greek. τέλος is the " end " and μέρος is the " part " . Telomere is the end region of DNA, which can be visually compared with the plastic tip of the laces. The main distinguishing features of this section are the fulfillment of the protective function and the lack of ability to connect with other chromosomes or their fragments.

As we know, human cell DNA has 23 chromosomes. The ends of each of them are necessarily protected by such “ tips ” . Chromosome telomeres protect the genetic program and are responsible for the integrity of DNA.

Bit of theory

Telomera is a term coined in 1932 by G. Miller. In humans, as in the vast majority of eukaryotic organisms (consisting of cells with nuclei), this is a special linear chromosomal DNA, which consists of a series of tandem short repeats.

Thus, in the telomeric regions, the nucleoprotein complex — the telomeric structural heterochromatin — is formed. It is formed by DNA and proteins that specifically bind to telomeric DNA repeats . The latter are conservative sequences. In us, as in all vertebrates, such a DNA repeat is a strictly defined sequence of TTAGGG nucleotides. Most of the plant world is TTTAGGG. In insects - TTAGG.

Researchers from the University of Cardiff found that the limiting length of a person’s telomere, at which the chromosomes connect to each other, is 12.8 telomeric repeat.

History

The revolutionary approach to the telomere effect has been outlined not so long ago:

• In 1971, a scientist from Russia A.M. Olovnikov first put forward the hypothesis that telomeres are shortened with every cell division. The shorter this “ tail ” , the less is the cell’s resource for further division.
• The experimental confirmation of the Russian hypothesis was announced 15 years later by the English researcher Howard Cook . But here the first inconsistencies of the theory have already been identified: the cells of muscles and nerves do not divide, respectively, the number of telomeres in them cannot decrease. But at the same time, these tissues age with all others. This issue is still open, serves as a reason for scientific debate.

• In the early 70s, the same A. M. Olovnikov predicted the existence of the telomerase enzyme, which is able to " complete " the ending telomeres.
• In 1985, telomerase was found in ciliates, then in yeast, plant and animal cells . As for humans, such a valuable enzyme was found only in the reproductive system - in sperm and ova, and, oddly enough, in cancer cells. Telomerase makes these particles virtually immortal, as it forms an endless chain of telomeres, which allows the cell to divide forever. But the rest of our somatic tissues do not contain such an enzyme in their constituents, which is why their cells age and die over time.

The importance of telomeres

Speaking of the fact that these are telomeres , we distinguish their distinctive characteristics:

• Do not contain genetic information.
• There are exactly 92 telomeres in each cell of our body.
• Responsible for genome stability.
• Protect chromosome replication from accidental fusion and degradation.
• Protect cells from aging, mutations and death.
• Responsible for the structural integrity of chromosome endings.

Telomeres and cell life

As you know, new cells are obtained by dividing the mother in two. Accordingly, chromosomes, as well as telomeres, are shared with it. With each division, the number of these protective “ tips ” decreases. As soon as their number becomes so small that the next division becomes impossible, the cell dies.

So the effect of telomeres affects the biological age of a person and any other living creature. With a decrease in the number of these protective elements, we are aging, as in our body there are fewer and fewer cells that are able to divide and renew the tissues that make up all vital organs.

Based on more than 8 thousand studies, the following can be stated:

• Long telomeres provide longevity.
• Short telomeres are associated with the steady aging of the body, regardless of the chronological age of a person.

But is it possible to “ lengthen ” telomeres?

Stop aging

Having established that telomere is one of the effective properties of controlling the biological age of a person, scientists conducted a number of experimental studies. The panacea was found in the form of telomerase - an amazing enzyme that has the property to complete the almost consumed telomeres. As soon as the protective “ tip ” of DNA is restored, the cell has a resource for further division, and therefore for the renewal of the tissues of our organs, which slows down the aging of the body as a whole.

How to “ lengthen ” telomeres? With the help of an enzyme that synthesizes the nucleotide sequence of TTAGGG at the terminal regions of DNA (telomeres) - telomerase . It has a number of worthy properties:

• Creation of a matrix along which critically short telomeres are completed.
• Extension of cell life.
• Protecting the entire body from premature aging.
• Prevent telomere length reduction.
• It makes it possible for an " elderly " cell to regain youth - to function and share like a young one.

Telomerase - the elixir of youth?

In 1997, scientists from the University of Colorado (USA) obtained the miracle enzyme gene. Already in 1998, their colleagues from the southwestern medical center of the University of Texas (Dallas) introduced the telomerase gene into somatic cells of a person - skin, vascular, visual epithelium. That is, in those that by their nature do not contain this enzyme.

And what is the result? The genetically modified cell remained quite viable, while telomerase did its job! The enzyme, as in germ and cancer cells, “ sewed ” telomeric nucleotide sequences, which is why the division of this particle in the body did not affect the telomere length. So far, in this way, it has been possible to extend the cell life by 1.5 times.

For this discovery in 2009, scientists D. Shostak , C. Grader, E. Blackburn was awarded the Nobel Prize, which is why there is no doubt in the seriousness of the research.

How to lengthen telomeres yourself?

In many countries, you can get tested for telomeres - a test that allows you to identify their length in your cells. But what if your resource runs out?

Scientists have revealed that we ourselves can lengthen our telomeres. Moreover, a number of completely simple solutions:

• Healthy eating
• Active lifestyle.
• Prevention of prolonged stressful situations.
• Confidence in the support of loved ones and friends.

And this is not another call for healthy lifestyle, but the results of research by scientists at the University of California (San Francisco). The experiment lasted 5 years. The “ subject ” was a group of men who showed prostate cancer in the first stage. 10 participants changed their lives in accordance with the above, and 25 did not do anything.

As a result, in those who have switched to a healthy life, the telomere length has increased by 10%. And this is the average result: the more people made positive changes, the more actively the telomere chain lengthened. But in the other part of the observed group, its length decreased by an average of 3%.

Cancer and immortality

Purely hypothetically, telomerase , introduced into the cells of the human body, makes them eternal, and itself immortal. But do not forget that this is a cancerous enzyme, the main reason for the malignant degeneration of matter. Oncology is therefore difficult to defeat because cancer cells are immortal. And it makes them exactly telomerase .

Hence the question: "But will cells modified by this enzyme degenerate into cancerous ones?" Nature cannot afford to deceive a person: theoretically we can make the body immortal, but it will inevitably die from cancer.

Thus, the influence of the telomere length on our biological age is recognized by the scientific community, although the theory causes a lot of controversy. And also simple rules of life have been revealed that will help us enjoy our youth longer without any elixirs of immortality.