Nobel 2009: more than for "aging and cancer"

These are well-deserved Nobel prizes, but aging has nothing to do with it
Evgeny Nudler, Snob magazineThe new Nobel Prizes in Physiology and Medicine were received, as they said, for the fight against aging and cancer.

There is always some catchy phrase being said here, but in fact the award is given according to the totality of merits, which are difficult to explain to a wide audience.

The Nobel Prizes in Physiology and Medicine this year were given to three scientists. Two (Elizabeth Blackburn and Carol Greider) were once professors and graduate students; in the mid–80s they discovered the enzyme telomerase, a biomachine that constantly conjures chromosomes in our cells. And another person, Professor Jack Shostak, found out everything about telomeres – the sections of chromosomes over which telomerase conjures. In addition, he made a discovery that is not mentioned in the press, but most likely also influenced the decision of the Nobel Committee: Shostak showed how RNA life worked in those distant epochs when there was no DNA on the planet. Today it is the dominant theory of the origin of life on Earth – Shostak's experiments gave it a solid foundation.

The discoveries of today's Nobelists are presented through the winning theme of cancer and aging – in fact, their merits are both more and less. Today it is clear that telomeres and telomerase are not directly related to aging (I will explain why now). But looking at things more broadly, these discoveries turned a new page in the history of science. I had dinner two months ago with Liz Blackburn in NY, among other things we discussed the upcoming Nobel awards, and I said that sooner or later she would receive the prize – the only question is when. It turned out – very soon.

Below is a detailed explanation of the essence of the discovery.

As it became known in 1953 (the discovery of Watson and Crick), hereditary information is stored in a cell in the form of a double helix, a double–stranded DNA molecule; a person has about two meters of such a double helix in the nucleus of each cell.

For convenience, this endless spiral is divided into 23 unequal segments; each is repeatedly twisted and packed – as a result, chromosomes are obtained. People saw them under a microscope back in the XIX century. When it's time for the cell to divide, each chromosome doubles. A special enzyme is responsible for this. Here's how it happens:

The enzyme unwinds the double strand of DNA and completes the missing chain on each half. Two strands of DNA are obtained, which diverge into daughter cells.

By the 80s, the following, at first glance, private question remained unresolved: how is the very tip of DNA copied? The zipper on the clothes has a section for which the carbine is held. And how is it here?

For the first time, the problem of shortened chromosomes was identified by our compatriot Alexey Olovnikov, whom I know very well. He was the first to propose the "telomeric" hypothesis of aging. Joseph Gall, Liz Blackburn and Jack Shostak experimentally established that at the end of each chromosome there are areas that do not carry genetic information; he called them telomeres (Greek – "end parts"). From everything that we managed to find out about them, it became clear that with each division, telomeres should shorten: after all, there is their most extreme tip, for which an enzyme that copies DNA should hold.

Blackburn and Grader figured out how nature gets out of the situation. They found that after division, a special enzyme – telomerase – completes telomeres. This is a very distinctive process, because usually the DNA in the cell is completed in the first way – by completing the mirror image on each half of the spiral.

The glowing tips of chromosomes are telomeres; telomerase completes them after doubling the main part of the chromosome.

All these details may seem private, but they immediately became the focus of attention of scientists around the world. In the 90s, many believed that one of the mechanisms of aging was the termination of telomerase; then the chromosomes would begin to melt, the genome would break down – and the body would die. But it turned out that our cells do not need so many divisions in their entire life. If you turn off telomerase genetically, mice live no less: the margin of telomere length is sufficient to last the right time – until cancer or stroke kills you. Telomerase is needed not to save the body, but to save the genus: if telomeres were melting all the time, it would begin to affect the next generation.

The discoveries of Blackburn, Grader and Shostak have given a promising approach to cancer treatment. The fact is that, unlike normal cells, cancer cells divide very often, endlessly. And for them, disabling telomerase turns out to be fatal – here you can wait for news in the coming years.

And, finally, the most important thing is that these discoveries turned out to have much broader applications. Armed with new knowledge, Shostak learned how to make artificial chromosomes that live well and divide in a cell. It was with this that the revolutionary transformations in genetics, genomics and molecular biology began. It has become possible to embed into the genomes of experimental organisms pieces of alien or artificial genomes with a length of millions of "letters". And one more thing: the first fully read genomes relied on the same technology.

Portal "Eternal youth" http://vechnayamolodost.ru06.10.2009