Simon Braun
Human DNA contains over 20,000 genes and would stretch nearly two metres if fully uncoiled. To fit this enormous amount of information into a tiny space within a cell — just 10 to 100 micrometres in diameter — it must be tightly compacted. This is the job of chromatin, a complex of proteins that packages and condenses DNA within the cell nucleus. However, in this condensed form, the DNA is unreadable and therefore inactive. Other proteins are needed to remodel chromatin, allowing access to specific DNA sequences at the right time and place, so the cell can read the genetic instructions that determine its function within the body.
“These two proteins could become promising therapeutic targets for diseases linked to disrupted chromatin remodelling — and potentially offer treatments that are less toxic than current options,” says Simon Braun, assistant professor in the Department of Genetic Medicine and Development at the UNIGE Faculty of Medicine.
This epigenetic mechanism — the regulation of gene expression — can sometimes go awry. When the wrong region of DNA is opened, it can disrupt the cell’s identity — in other words, its function. “This is what we observe in skin cells, for example,” explains the expert. “If inappropriate regions of chromatin are exposed, parts of the genome that promote abnormal cell growth can become active, potentially leading to skin cancer. If this dysregulation occurs in developing neurons, it may also contribute to neurological disorders such as autism.”