A research carried out by Dr. Klaus Hansen's group at BRIC, University of Copenhagen, shows that external factors can stress our cells by controlling our genes.Stress is one of society's major problems and sooner or later it affects everyone, and not only at a psychological level.
Body cells can be affected by stress because of pollution, tobacco smoke, bacterial toxins and many other external factors that forced stressed cells to react in order to survive and maintain a normal function.
In extreme cases, this reaction to stress can lead to diseases.
Dr. Klaus Hansen said that “stress-activating factors can control our genes by turning on certain genes that were supposed to be silenced.
“It is very important that some genes are on and others are off in order to ensure normal fetal development and correct function of our cells later in life,” he added.
The discovery of stress activating silenced genes was made by Simmi Gehani, PhD-student in the Hansen group.
He found that even short variations in gene activation can be devastating for cellular identity during the development of the fetus, but they also can have serious consequences in the adult body.
“For example, one could imagine that prolonged stress causes nerve cells in the brain to produce hormones and other signaling molecules they do not normally produce and this can disturb normal brain function,”Gehani said.
Dr. Hansen's group wanted to find out what turns genes on and off, so they studied a complex called PRC2.
“We know that different protein complexes can associate with specific proteins (histones) to which DNA is wound around and thereby determine whether the genes are active or inactive,” said Hansen.
“Small chemical groups can cause protein complexes to bind to histones which can control gene activity”, and PRC2 can attach small chemical groups - methyl groups - to the histones.
The genes are turned off when protective complexes bind to the histones, and are turned on when the complexes are lost and cells are exposed to external stress factors.
The complexes are lost because the stress factors instruct an enzyme named MSK to attach another chemical group - a phosphate group - to the histones neighboring the methyl group.
The phosphate group neutralizes the effect of the methyl group and turns specific genes on.
The results is that genes that were supposed to be off are now on, and “this may disturb cellular development, identity and growth” explains Simmi Gehani.
In other words, without damaging our genetic code external stress factors can control the activity of our genes.
The results of this research are published in the renowned international journal Molecular Cell.