Unfurling our heritage
Our most precious things are kept where they meet the least damage. Out of reach on a shelf, in the depths of a drawer, deposited in a bank or perhaps parked in the garage. Frequently, too, a layer of protection is added by wrapping the valuable item in cloth or placing it in a padded box. Nature does exactly the same with one of its most treasured commodities: DNA. In eukaryotes, not only is our genetic heritage tucked away in the fortress-like nucleus of cells but it is also swathed in numerous molecules to form what is known as 'chromatin'. Protecting DNA is paramount, for obvious reasons. However, to survive, cells must have access to the genes their DNA carries in order to express them. This implies that cells need to dismantle the chromatin barrier, at different locations and at any given time. It's not so much dismantling chromatin, really, as remodelling it in such a way that genes are sporadically laid bare and thus open to transcription. One of the numerous proteins involved in chromatin remodelling is ATRX, so called because it is found on the X chromosome of mammals. An intriguing fact: in marsupials, ATRX is also found on their Y chromosome.
