Russian and European biologists have figured out how the "heart" of telomerase, an enzyme, the inclusion of which in the body of an adult can make its cells immortal, works, says an article published in the journal Nucleic Acids Research.
“These data bring us closer to understanding the structure, functioning and regulation of telomerase. In the future, they can be used to create drugs that will both increase telomerase activity and increase the life span of cells, and decrease it in order to deprive cancer cells of immortality,”notes Elena Rodina, a biochemist at Moscow State University.
The cells of the embryo and embryonic stem cells are virtually immortal from the point of view of biology - in an adequate environment, they can live almost forever and divide an unlimited number of times. In this case, the cells of the body of an adult after 40-50 cycles lose the ability to divide and enter the aging phase.
These differences are due to the fact that each division of adult cells leads to a reduction in the length of their chromosomes, the ends of which are marked with special repeating segments, the so-called telomeres. When telomeres become too small, the cell stops participating in the life of the body. This is thought to protect him from developing cancer.
As Rodina and her colleagues explain, this never happens in embryonic and cancer cells, since their telomeres are renewed and lengthened with each division thanks to special enzymes - telomerases. The genes responsible for the assembly of these proteins are turned off in adult cells, but in recent years, scientists have been actively thinking about whether it is possible to prolong human life by forcibly turning them on or creating an artificial analogue.
Biologists and chemists from Moscow State University, Moscow Institute of Physics and Technology and other Russian and European research centers took the first step towards solving this problem by studying the structure of the central part of the enzyme and finding out how it interacts with RNA and DNA molecules during telomere lengthening in single yeast cells.
Experiments have shown that this protein is similar in principle to a copier. It reads a single sample - an RNA molecule - and copies it onto the DNA of a future cell, and then glues the new copies together.
Biologists consider one of its regions, named TEN, to be a key part of this process and of the entire telomerase in general. It is assumed that it plays the role of a kind of controller: it monitors the length of telomeres, determining their beginning and end by special sequences of letter-nucleotides, and is responsible for their attachment to a common DNA strand and starting the assembly of the next region.
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Interestingly, the structure of TEN is almost the same in most multicellular creatures, suggesting that it has played a critical role in evolution over the past 500 million years. Scientists hope that further study of yeast telomerases, which work constantly, and their comparison with similar human enzymes will help to understand why these proteins are disabled in our cells, as well as to find a key to controlling their activity.
