Background: DNA polymerase β (pol β) is a key enzyme of base excision repair pathway. It is a 1-kb gene consisting of 14 exons. Its catalytic part lies between exon 8 and exon 14. Exon 12 has a role in deoxyribonucleotide triphosphate selection for nucleotide transferase activity. Methods: Genomic DNA was isolated from ovarian carcinoma samples. Single strand conformation polymorphism...

One of the major early steps of repair is the recruitment of repair proteins at the damage site, and this is coordinated by a cascade of modifications controlled by phosphatidylinositol 3-kinase-related kinases and/or poly (ADP-ribose) polymerase (PARP). We used short interfering DNA molecules mimicking double-strand breaks (called Dbait) or single-strand breaks (called Pbait) to promote DNA-de...

In the current model of DNA SSBR, PARP1 is regarded as the sensor of single-strand breaks (SSBs). However, biochemical studies have implicated LIG3 as another possible SSB sensor. Using a laser micro-irradiation protocol that predominantly generates SSBs, we were able to demonstrate that PARP1 is dispensable for the accumulation of different single-strand break repair (SSBR) proteins at sites o...

Peroxynitrite (ONOO-/ONOOH) is a powerful oxidant that can induce mutations and cause single-strand breaks in plasmid supercoiled DNA. The selenium-containing compound ebselen rapidly reacts with peroxynitrite. Therefore, ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] and other selenium-containing molecules, selenomethionine and selenocystine, were studied as agents protecting DNA from singl...

DNA polymerases purified from several sources are characterized by replication of the 3'-hydroxy-terminated strand of a helical template. Failure to achieve simultaneous replication of the 5'-strand leads to aberrations in the synthesized DNA, described as nondenaturability and branching. Aberrations in synthesized DNA were not observed when (a) the 5'-strand was destroyed by a specific nucleas...