Example of the structure of quadruplex DNA or G4

Example of the structure of quadruplex DNA or G4. This is a quadruplex DNA that forms in the promoter region of the c-myc gene (Protein Data Bank ID: 1XAV). Quadruplexes are non-usual DNA structures that offer an additional level of gene regulation. In contrast to the permanent double helix structure of DNA, the very dynamic structures of quadruplexes comprise four strands rotating around each other. G4s may form in no less than 716,000 locations in our genome. They may be involved in a number of biological processes that are indispensable to the correct operation of the cell, such as chromosome stability or DNA replication. This might explain their role in the development of several rare neurodegenerative or infectious diseases.