Piquant details from the life of centenarians
The long-lived worm has become one large sexual organ
Peter Baranov, Infox.ruMutations that increase the lifespan of roundworms by almost ten times turn the entire worm's body into a kind of one large sex gland.
Gary Ruvkun from Harvard Medical School and his colleagues found that all the cells of such worms in their structure and biochemical composition are very similar to gametocytes, from which sperm and eggs are formed. Of course, there is no talk of cardinal "reprofiling", but the acquired ability to a large number of consecutive divisions with minimal accumulation of genetic errors turns out to be very useful.
The phenomenon of active longevity does not give scientists peace of mind. In January 2008, Walter Longo managed to increase the lifespan of yeast tenfold by knocking out the RAS2 and SCH9 genes that conduct an intracellular signal from insulin-like growth factor (IGF). A month later, Robert Reis reported on a similar success, but with a multicellular organism — the fate of the nematodes Caenorhabditis elegans submitted to him, too, after interfering with the IGF.
The effect of the latter on life expectancy is realized through the transcription factor DAF-16, selectively regulating the work of numerous genes. Therefore, all cells of such mutant long-lived worms turned out to be significantly more resistant to genotoxic stress, and they were divided with fewer errors. Ruvkun and co-authors of the publication in Nature noticed that gametocytes forming spermatozoa and eggs normally have similar properties.
In a certain sense, these cells are immortal. After all, their descendants give rise to all the cells of the daughter organism. Including, by the way, the next gametocytes. Those, in turn, form gametes again, they merge again with the formation of a zygote, which gives rise to all cells of the body, including the sex glands, and so on indefinitely.
A more detailed analysis of intestinal cells and the integuments of long-lived worms only expanded the list of similarities. First, the ability to divide returned to them. Secondly, RNA granules characteristic of gametocytes appeared in their cytoplasm. It is believed that these granules consist of interfering RNAs, which, in addition to regulating the work of their own genes, provide antiviral protection. Thirdly, gametocyte-specific marker proteins appeared, for example, PGL-1.
The final experiment was to turn off the genes characteristic of gametocytes throughout the body of already genetically defective long-lived mutants. The principle of double negation (true, in this case of different genes) worked — such "twice defective" worms lived no longer than their wild counterparts.
It is possible that a similar phenomenon occurs in our body, because starvation on animals has about the same effect as the genetic shutdown of IGF, only much weaker.
Portal "Eternal youth" http://vechnayamolodost.ru/15.06.2009