Researchers at the US National Institutes of Health (NIH) have discovered areas in the DNA of neurons that accumulate single-strand breaks.
Scientists at the US National Institutes of Health (NIH) have discovered areas in the DNA of neurons that accumulate a certain type of damage (called single-strand breaks, or RRs). Their accumulation seems to be unique for neurons and casts doubt on the generally accepted ideas about the cause of DNA damage and its potential consequences for neurodegenerative diseases.
Because neurons require a lot of oxygen to function properly, they are exposed to high levels of free radicals. These are toxic compounds that can damage DNA inside cells. Usually, such processes happen by accident. However, in this study, neuronal damage was often found in specific areas of DNA – enhancers that control nearby genes’ activity.
Fully mature cells, such as neurons, do not need all of their genes to be active at the same time. One way cells can control gene activity is through the presence or absence of a chemical tag – a methyl group – on a particular building block of DNA. A closer examination of neurons showed that a significant number of single-strand breaks occur when methyl groups are removed, which usually makes this gene available for activation.
The explanation proposed by the researchers is that removing the methyl group from the DNA itself creates an OR. At the same time, neurons have several recovery mechanisms. This casts doubt on the popular belief that DNA damage is a process that must be prevented. On the contrary, at least in neurons, it is part of the normal turning genes process on and off. Also, this means that disruption of the repair process, rather than damage to the DNA itself, can potentially lead to neurodegenerative diseases.