Scientists have discovered how HIV was transmitted from monkeys to man

© AP Photo / Wong Maye-Simpanse he lights a cigarette at the zoo in Pyongyang, North KoreaScientists have discovered how HIV was transmitted from monkeys to man© AP Photo / Wong Maye-E

The immunodeficiency virus of monkeys could easily adapt to life in the human body due to the absence in the genome of the earliest victims the «right» version of a specific gene that interferes with the retroviruses embedded in the DNA of cells, according to an article published in the journal PLoS Pathogens.

«We assume that the stable molecules of the enzyme A3H be an insurmountable barrier to VIO, which today does not allow it to infect human cells. Of course, there are other protection mechanisms, such as protein Teterin, however, the virus is able to circumvent them. It seems that HIV originated in the body of those people who have A3H was unstable,» write Karsten of myunk (Carsten Muenk) from the Heinrich Heine University in düsseldorf (Germany) and his colleagues.

The relatively sudden emergence of HIV in Africa in the 80 years of the last century and its rapid spread over the Earth has led many scientists and ordinary people think, where did this virus. Quite quickly emerged, as many believe the myth that the source of the first versions of this virus were chimpanzees or other primates that could infect the inhabitants of the Congo and other countries in West Africa, where he first found HIV.

Many scholars today doubt this, noting that a similar scenario of spread of HIV was extremely unrealistic – the successful evolution of the virus and its adaptation to work inside the cells of new media, in their opinion, was to require more time.

Additionally, infection of monkeys with the human immunodeficiency virus does not lead to negative consequences for their health, which gave rise to doubts in the direct transmission of the virus from Primate to humans. However, recent experiments and genetic studies show that the VIO truly is the progenitor of HIV, and that it is very easy to «stepped» through the barrier between species.

Of myunk and his colleagues uncovered the «secret» history of this transformation, and explain why HIV is relatively recent, watching, with some components built-in of the human immune system interacts VIO while trying to infect the cells.

Attracted the attention of scientists the genes and related proteins of the A3 family, playing the role of a kind of «anti-virus» in the human cells. These molecules recognize single strands of viral RNA, join them and spoil their parts, which contains cytidine, one of the four «letters» of the genetic code. Retroviral enzymes responsible for the «implementation» of the virus ‘ genes in human DNA, you can’t to read this RNA and the infection stops.

As shown by the experiments of biologists, one of these proteins, A3H, very effectively stops the multiplication of SIV in human cells, but does not preclude the integration of its DNA into the genome of chimpanzees and other monkeys. This is an unusual divergence of interested scientists, and they tried to figure out what it was by comparing the structure of A3H in the genomes of apes and humans.

The answer to this riddle was extremely easy – it turned out that the DNA of people there are two varieties of genes encoding A3H, one of which produces a relatively stable and active molecule (type II) and the other proteins that the virus can easily neutralize (type I). As a rule, most people are carriers A3H second type, whereas virtually all of the chimps have only the first type of these proteins.

This feature of the apes, says of myunk, at the same time explains why SIV doesn’t infect people, and tells the story of becoming HIV. Apparently, the first victim of the future HIV was a carrier of the first type A3H, which allowed the virus to take root in her body to mutate and spread in an even greater number of people with a similar version of the protein. Eventually he learned to fight and with the protein of the second type.

As it happened, scientists still can not say the ancestor of HIV could enter the body of the «patient zero» of the meat of infected monkeys, and in other ways — through blood, wounds or other secretions. Further study A3H and how these viruses interact with him, according to Munce, will help to understand whether it is possible to use this protein to protect people not only from VIO, but from the main virus of the century.