Figure 5. Timeless depletion slows replication of telomere, but not nonrepetitive DNA templates in vitro. (A) Schematic representation of the replication template, pT2AG3 plasmid linearized with BbsI enzyme. The largest fragment (right) contains ~1.8 kb of telomere repeats. (B and C) Autoradiography of radiolabeled replication products from in vitro SV40-mediated DNA replication reactions using the indicated cell extracts. Reactions were stopped at the indicated times and samples were purified, digested, and separated by agarose gel electrophoresis. In (B) no exogenous human protein added. In (C), recombinant TRF1 protein added. (D and E) Quantification of the replication products, at the indicated times, as shown above (in B and C, respectively). Top Panels are telomere DNA products, and bottom Panels are non-telomere DNA products. Representative results of repeat experiments are shown.