Function and targeting of G-quadruplexes.

Guanine-rich sequences of DNA and RNA may fold in vitro and in vivo into G-quadruplexes, four-stranded helical structures held together by a guanine core. G-quadruplexes have various biological functions, including inhibition of telomerase and the regulation of gene transcription and translation, and have become an active target for drug development, particularly for novel anticancer therapies. The physiological functions of G-quadruplexes are discussed in this review and the current knowledge of G-quadruplex ligand and drug development is outlined.