DNA polymerase δ stalls on telomeric lagging strand templates independently from G-quadruplex formation.

ABSTRACT: Previous evidence indicates that telomeres resemble common fragile sites and present a challenge for DNA replication. The precise impediments to replication fork progression at telomeric TTAGGG repeats are unknown, but are proposed to include G-quadruplexes (G4) on the G-rich strand. Here we examined DNA synthesis and progression by the replicative DNA polymerase δ/proliferating cell nuclear antigen/replication factor C complex on telomeric templates that mimic the leading C-rich and lagging G-rich strands. Increased polymerase stalling occurred on the G-rich template, compared with the C-rich and nontelomeric templates. Suppression of G4 formation by substituting Li(+) for K(+) as the cation, or by using templates with 7-deaza-G residues, did not alleviate Pol δ pause sites within the G r

SUBMITTER: Lormand JD 

PROVIDER: S-EPMC3905856 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature