27 June 2011

Hereditary stress

The effects of stress are inherited
CNews R&D based on the materials of R&D Magazine: Mechanism for stress-induced epigenetic inheritance uncovered in new studyScientists at the RIKEN Institute of Physico-Chemical Research in Japan have deciphered the mechanism by which the effects of stress in fruit flies are inherited for many generations.

This mechanism consists in changing the structure of chromatin, the material of the cell nucleus consisting of DNA, RNA and proteins.

In recent years, scientists have shown increasing interest in the phenomenon of epigenetic heredity. The meaning of this phenomenon is that the genome, through epigenetic (chemical) labels and other structural modifications, transmits much more information to the next generation than is encoded directly in the DNA sequence. In earlier studies, it was found that various stressful influences induce the appearance of such epigenetic changes, but the underlying mechanisms of this process were not clear.

To clarify these mechanisms, researchers working under the leadership of Shunsuke Ishii studied the activity of the activation transcription factor-2 (from the English activation transcription factor-2, ATF-2), belonging to the family of transcription factors regulating changes in gene expression in response to environmental influences. Earlier studies have shown that in the absence of stress, transcription activation factor-2 blocks the activity of certain genes by forming heterochromatin, a tightly packed variant of chromatin, whose condition is inherited through epigenetic mechanisms.

When studying mutations of the transcription activation factor-2 (dATF-2) gene in fruit flies, scientists observed changes in the structure of heterochromatin. Further analysis showed that heat shock and osmotic stress at the early stages of embryo formation also alter the activity of this gene, which, in turn, releases neighboring genes "packed" in it from heterochromatin. This can lead to the appearance of new signs in the body that are transmitted to the next generations.

The figure shows schematically, using the example of an insect with a dATF-2 mutation,
the release of a gene that changes the color of flies' eyes is depicted
from white (in the wild type) to red.

The researchers note that there is a gene similar to ATF-2 in the human genome, so it is logical to assume that the described mechanism also takes place in our cells. The epigenetic changes occurring in this case can affect any processes and signs of the body, including metabolism, behavioral characteristics and predisposition to diseases. Perhaps they even play a role in the growing spread of so-called "diseases of civilization" and mental illnesses. If this is the case, then, theoretically, the situation can be corrected with the help of existing drugs that affect enzymes that modify the ATF-2 gene under stress.

Portal "Eternal youth" http://vechnayamolodost.ru27.06.2011

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