Scientists at the Institute for Biomedical Research have discovered a vulnerability in the DNA of humans and animals. It turned out to be the histone H1 protein, which is the main factor in protecting the genome from instability. Mutations in this compound lead to the death of the organism. The researchers' article was published in the journal Nature Communications.
Histones are involved in the packaging of DNA, which wraps around proteins, and help it fold into helical structures. In addition, they regulate the activity of individual genes and non-coding regions. There are several varieties of histones, but the functions of H1 were the least known.
In experiments with an animal model involving the fruit fly Drosophila melanogaster, scientists have found that suppression of H1 causes DNA damage and cell death. This occurs through loss of regulation over regions of the genome that are usually dense and almost inactive. As a result, defects accumulate in the process of transcription (the transfer of information from DNA to RNA molecules) and R-loops appear - structures of DNA and RNA, which are lethal to the cell.
The difference between flies and humans is that the insect has only one H1 variant, while humans have seven. The researchers first removed the histone from the wing buds of the Drosophila embryos, leading to the birth of wingless individuals. If the entire embryo is deprived of this protein, then the whole organism dies.