Researchers report that most genes are repressed through a mechanism by which methyl molecules are attached to DNA.
The cells of a given tissue can express only certain genes while others are silenced. This process, called gene repression, allows cells to perform specialized tasks that are different among various organs.
Previous studies have shown that genes are repressed when methyl molecules are attached to them ? a process called methylation ? but such studies have not shown that all genes are repressed exclusively by this modification.
Howard Cedar and colleagues show that methylation is the main gene repression mechanism, but other mechanisms ? such as the modification of chromosome proteins called histones and delays in DNA replication ? play an important role as well.
Article: “Role of DNA Methylation in Stable Gene Repression” by Laura Lande-Diner, Jianmin Zhang, Ittai Ben-Porath, Ninette Amariglio, Ilana Keshet, Merav Hecht, Veronique Azuara, Amanda G. Fisher, Gideon Rechavi, and Howard Cedar