Eukaryotic cells distinguish their chromosome ends from accidental DNA double-strand breaks by packaging them in a protective structure referred to as the telomere "cap." Here we investigate the nature of the telomere cap by examining events at DNA breaks generated adjacent to either natural telomeric sequences (TG repeats) or arrays of Rap1-binding sites that vary in length. Although DNA break...

Deoxyguanosine (dG) enhances the S phase cytotoxicity of camptothecin (CPT), a topoisomerase I (topo I) inhibitor, but by contrast does not affect the toxicity of VM26, a topoisomerase II inhibitor. The 80% survival of S phase human fibroblasts after a 60 min exposure to 0.2 microM CPT is reduced by half in the presence of 25 microM dG. G1 cells are resistant to CPT toxicity, though the levels ...

abstract this paper attempts to re-investigate the catching-up (stochastic convergence) hypothesis among the selected 16 oecd countries applying the time series approach of convergence hypothesis with annual data over one century. to reach this aim, we propose a model which specifies a trend function, incorporating both types of structural breaks – that is, sharp breaks and smooth shifts using ...

DNA double strand breaks (DSBs) are abrasions caused in both strands of the DNA duplex following exposure to both exogenous and endogenous conditions. Such abrasions have deleterious effect in cells leading to genome rearrangements and cell death. A number of repair systems including homologous recombination (HR) and non-homologous end-joining (NHEJ) have been evolved to minimize the fatal effe...