As a fertilized egg develops into a full grown adult, mammalian cells make many crucial decisions closing doors of opportunity as they adopt careers as liver cells, skin cells, or neurons. One of the most fundamental mysteries in biomedicine is how cells make such different career decisions despite having exactly the same DNA. By using a new kind of genomic technology, a new study unveils a special code not within DNA, but within the so-called chromatin proteins surrounding it that could unlock these mysterious choices underlying cell identity.
A research team led by scientists at the Broad Institute of Harvard and MIT and the Massachusetts General Hospital has created genome-wide chromatin maps for embryonic stem (ES) cells and two cell types derived from them, by applying a powerful new technology for sequencing DNA. The work, published in the July 1st advance online edition of Nature, provides a framework for mapping the complete chromatin landscape of almost any kind of cell. One of the most surprising findings suggests that cells contain an explicit chromatin-based code that reveals the developmental choices they have already made as well as those decisions that lie ahead.
Unraveling the mysteries of chromatin holds great promise for understanding how cells in the body with nearly identical DNA assume such different forms and functions, said co-senior author Bradley Bernstein, an associate member at the Broad Institute and an assistant professor at Massachusetts General Hospital and Harvard Medical School. By applying a new technology for sequencing DNA, we have been able to look across the genome at chromatin, with greater resolution and efficiency than ever before.
Chromatin proteins are more than just packing material for the genome. By virtue of different chemical groups fastened to them, these proteins influence which parts of the double helix are open or not to the cellular machinery, thus controlling which genes
Contact: Nicole Davis
Broad Institute of MIT and Harvard