Neurons are not born
The role of "junk" DNA in the formation of neurons has been discovered
Georgy Golovanov, Hi-tech+
There comes a time for every cell in the body when it has to decide what it will do for the rest of its life. For the first time, scientists have managed to establish that ancient viral genes, which were previously considered "junk DNA", play an important role in this process.
In the course of evolution, the human genome accumulated thousands of endogenous retroviruses. As a result, almost 8% of DNA has remnants of these genes. Previously, they were thought to be inactive or "junk", but recent studies have shown that they are involved in the development of embryos, the growth of some tumors and nerve damage in the case of multiple sclerosis.
Scientists from the National Institute of Health of Great Britain have shown that deactivation of the HERV-K gene can lead to the formation of a neuron from stem cells, says the NIH press release Turning off “junk DNA" may free stem cells to become neurons.
Article by Wang et al. Regulation of stem cell function and neuronal differentiation by HERV-K via mTOR pathway is published in the journal PNAS – VM.
Taking blood from healthy volunteers, the researchers genetically transformed it into induced pluripotent stem cells, which can then turn into any type of cells in the body. To their surprise, they found that the surface of stem cells is lined with a large amount of HERV-K, a subtype of HML-2, a protein shell to which viruses infecting the cell are often attached.
Under the influence of drugs on the cell, these proteins gradually disappear: after the first intake, the cell turns into an intermediate nerve stem cell, after the second it finally becomes a neuron. This process can be accelerated or slowed down.
The team also found that interactions on the stem cell surface between HML-2 and another CD98HC protein can limit its differentiation by triggering internal chemical reactions that control the growth of cells and tumors. In the future, researchers intend to understand how the HERV-K genes form the "wiring" of the nervous system.
A group of scientists from the United States proved last year that mutations in the non-coding part of the genome can cause autism. This is the first work that indicates the relationship of these variations with the development of the human nervous system.
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