New insights on how cells protect and repair DNA damages

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New research that looked into the functions of histones has revealed that beyond the role of making sure that DNA is packed properly, they also possibly play a role in repair of DNA damages.

Researchers at University of Copenhagen reveal that their findings could pave way for better treatments for diseases caused by cellular changes including cancer and immune deficiency syndrome.

Histones have long been studied by researchers across the globe and information about their types and their major functions is already known. Histones enable the tight packaging of DNA strands within cells, which could be as long as two metres in length and the cells usually approx. 100,000 times smaller.

On a very general level, there are five types of histones – four core histones that are placed like beads on the DNA strands, which themselves are curled up like a ball of wool within the cells. In addition to enabling the packaging of the DNA strands, histones play a central part in practically every process related to the DNA-code. The four core histones have so-called tails, and among other things they signal damage to the DNA and thus attract the proteins that help repair the damage.

Between the histone “yarn balls” there is this fifth histone, Histone H1, but up until now its function has not been thoroughly examined. Scientists used mass spectrometer, and discovered that H1 histone also helps summon repair proteins.

“I believe that there’s a lot of work ahead. It’s like opening a door onto a previously undiscovered territory filled with lots of exciting knowledge. The histones are incredibly important to many of the cells’ processes as well as their overall wellbeing,” says Niels Mailand from the Novo Nordisk Foundation Centre for Protein Research at the Faculty of Health and Medical Science.

“In international research, the primary focus has been on the core histones and their functionality, whereas little attention has been paid to the H1 histone, simply because we weren’t aware that it too influenced the repair process. Having discovered this function in the H1 constitutes an important piece of the puzzle of how cells protect their DNA, and it opens a door onto hitherto unknown and highly interesting territory,” Niels Mailand elaborates.

He expects the discovery to lead to increased research into Histone H1 worldwide, which will lead to increased knowledge of cells’ abilities to repair possible damage to their DNA and thus increase our knowledge of the basis for diseases caused by cellular changes. It will also generate more knowledge about the treatment of these diseases.

“The knowledge we generate can prove important to the development of more targeted treatments for diseases caused by cellular changes, including cancer. By mapping the function of the H1 histone, we will also learn more about the repair of DNA damages on a molecular level. In order to provide the most efficient treatment, we need to know how the cells prevent and repair these damages,” Niels Mailand concludes.