Guanine-rich telomeric sequences stimulate DNA polymerase activity in vitro.

Guanine-rich oligonucleotides and short telomeric DNA sequences can self-associate into G-quartet stabilized complexes. We discovered that this self-association can occur in sequencing reactions and that higher-order structures stimulate DNA polymerase to synthesize extended DNA strands. Base analogues were used to identify Hoogsteen base pairings as stabilizing forces in these stimulatory DNA structures. Scanning force microscopy confirmed that quartet-DNA was formed from these oligomers and that these extended, four-stranded structures could be bound by DNA polymerase. Since guanine quartet-stabilized structures are proposed to exist in vivo, such structures may stimulate DNA polymerization in vivo.