The IL-15Ra gene interferes with a bad runner
Gene goes on record: Powerful mice
Popular Mechanics by ScienceNOW publication:
Missing Gene Helps Mice Run for Hours
Ordinary laboratory mice are not too willing to run in the wheel. But if they "turn off" a certain gene, they enthusiastically run, spending many hours a day on these exercises. A similar gene exists in humans – perhaps it somehow explains the performance of record-breaking athletes.
In previous studies, the connection of the IL-15Ra gene with the work of muscles was demonstrated in the most obvious way. In a culture of muscle cells grown "in vitro", this gene controlled the synthesis of proteins necessary for muscles to contract. However, no one has yet studied how IL-15Ra is revealed in a living organism.
Only recently, Tejvir Khurana's group took up this issue. Scientists have created a line of laboratory mice completely devoid of the IL-15Ra gene. The changes were the most unexpected. Every night, when the mice are most active, sensors mounted on the running wheel recorded that these mice are taken to run around the wheel – and run six times longer than their "normal" relatives.
It was difficult to say what this was due to, because such behavior can be associated not only with an excess of energy, but also, for example, simply with increased nervousness. The questions were dispelled by the study of muscle tissue samples taken from "running mice". The cells of their muscles showed a real degeneration, saturation with energy-producing organelles-mitochondria and a large number of actin-myosin fibers lead to much greater endurance of such mice. Indeed, if such cells are stimulated by electricity, they contract longer and stronger than normal.
Dark grains in the images – mitochondria:
on the left – on a slice of the muscle of an ordinary mouse,
on the right are mice with the IL-15Ra–VM gene knocked out.
Credit: Emidio E. Pistilli and Tejvir S. Khurana,
Perelman School of Medicine/University of Pennsylvania
Recall that mice, like you and me, have several types of muscles. Skeletal muscles are responsible for the movement of the body and limbs, and they can (as, say, in the fingers and hands) be rapidly contracting, providing speed and accuracy of movements, but also getting tired faster, or slowly contracting (like the back muscles supporting the body in an upright position), but more resilient. Interestingly, the analysis of samples of "supermysh" obtained by Tejvir Khurana's group showed that switching off the IL-15Ra gene leads to the fact that rapidly contracting fibers turn into slowly contracting ones.
The researchers decided to switch from mice to humans. Of course, it wasn't about manipulating the human genome. Instead, they contacted their colleagues from Australia, who have accumulated an impressive database of genetic samples collected from top-level athletes, world champions and Olympic Games.
After studying them, the picture was confirmed: in athletes associated with endurance tasks – runners and long–distance cyclists - certain variants of the IL-15Ra gene were very widespread. 3/4 of such athletes had one of them. And although the functional differences between different variants of the gene are still unknown, now we know a variant suitable for certain sports. To determine your propensity for it, it is enough to conduct a simple genetic analysis.
Portal "Eternal youth" http://vechnayamolodost.ru26.07.2011