Figure 4.

Scheme illustrating suggested roles of quadruplexes. Quadruplex formation and recognition have various functions in biological processes and their dysregulation may be associated with human disorders, as seen from mutations in quadruplex-recognition proteins, quadruplex-resolving helicases (a) and quadruplex-forming sequences (b); as well as changes in the binding affinity and stability of telomere complexes (c); and generation of new quadruplex-forming motifs via triplet expansions (d); and transcriptional alteration (e). Arrows show connection of changes associated with quadruplex formation and recognition and influence of these changes to aging and diseases progression.