TELOMERE STRUCTURE AND FUNCTION

Telomeres, the termini of linear eukaryotic chromosomes, contain speci fic DNA sequences that are widely conserved. These sequences not only recruit telomere-specific proteins, but also give telomeric DNA the ab ility to fold into four-stranded DNA structures. Recent structural stu dies have shown that the repertoire of quadruplexes formed by the G-ri ch strand is larger than had been envisaged. Even more surprising is a novel four-stranded structure formed by the G-rich strand, called the i-tetraplex. Genetic and biochemical analyses have been used to ident ify proteins involved in telomeric DNA packaging and organization. The possibility that four-stranded structures may play a role in telomere function has been strengthened by the discovery that telomeric protei ns can bind to and promote the formation of G-quadruplexes.