Inside each of our body’s cells, DNA is stored in a structure called chromatin. This protects the DNA from damage, but it’s unclear exactly how it’s formed and maintained. Chromatin is difficult to study because most of the body’s cells repeatedly open it up to access, copy and repair the DNA. This activity was thought to be reduced in egg cells, or oocytes, which are resting inside the ovary. Now, researchers at the MRC Clinical Sciences Centre and Babraham Institute have shown this is not the case. The scientists studied mouse oocytes, in which chromatin is packed around the centre of the cell (left). In mice engineered to lack a protein called Hira, the chromatin couldn’t maintain its structure and the DNA dispersed (right). The team thereby showed Hira is essential for maintaining chromatin’s structure, and also that chromatin is just as dynamic in resting oocytes as in other cells.
Written by Deborah Oakley
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