European team of scientists supported by Marie Curie Actions has discovered how cells accurately inherit information that is not contained in their genes
While the adult human body's 10 trillion cells are genetically identical, they develop into distinct types of cells including nerve cells, skin cells and muscle cells. This distinctive quality is triggered by the activation of some genes and the inhibition of others. Specialised cells have the capacity to keep a memory of their individual identity by remembering which genes need to be active or not, even when making copies of themselves.
Led by Lars Jansen from the Instituto Gulbenkian de Ciência (IGC) in Portugal, researchers say that while this type of memory is not written directly into the deoxyribonucleic acid (DNA), it is heritable. Meanwhile, non-genetic or 'epigenetic' instructions usually appear to be contained in proteins, and control both genes and the arrangement of chromosomes.
The team discovered how one of these epigenetic organising centres is passed on from mother to daughter cells. The findings could help scientists determine how a glitch in the cell division process can trigger cancer. 'When cells divide, they make exactly two copies of all genes, to be passed on to exactly two cells,' explains lead author Mariana Silva, a doctoral student from the Jansen lab. 'A similar feat has to be pulled off for non-genetic information. But how does the cell copy a protein structure? And, how does it ensure just the right number of copies are made? This question is still mystifying scientists. We focused our efforts on the centromere because the key protein responsible for its epigenetic behaviour is known. Experts from the United Kingdom and the United States contributed to this study.