title: DNA double strand break repair in brain: reduced NHEJ activity in aging rat neurons.
abstract: Linearised pUC 19 DNA with cohesive, blunt and non-matching ends, generated by prior treatment with different restriction enzymes was presented as substrate to measure the NHEJ activity to repair DNA double strand breaks in extracts prepared from isolated neurons from neonatal, young adult and old rat cerebral cortex. Highest end joining activity was noticed with the substrates having cohesive 3' overhang (PstI) or 5' overhang (EcoRI) ends and this activity is significantly reduced with age. However, blunt and non-matching ends were very poorly repaired at all ages. Further, the end joining activity in neurons is not faithful and sequence changes occur during the repair process. Also, the end joining activity in old neuronal extracts, but not in young extracts, was found to decline very rapidly with time of cold storage. These findings, the first of their kind, thus demonstrate that neuronal cells have the capacity to repair DNA double strand breaks through error prone NHEJ mode and that the cohesive end joining activity decreases with age of the animal.
authors.affiliation: ICMR Center for Research on Aging and Brain, CRAB, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Andhra Pradesh 500046, India.
authors.forename: V N
authors.initials: VN
authors.lastname: Vyjayanti
authors.forename: Kalluri Subba
authors.initials: KS
authors.lastname: Rao
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000166:cytology*; D002457:Cell Extracts / Q000235:genetics; D002474:Cell-Free System / Q000737:chemistry / Q000378:metabolism; D004249:DNA Damage / Q000235:genetics*; D011088:DNA Ligases / Q000494:pharmacology; D004260:DNA Repair / Q000235:genetics*; D004587:Electrophoresis, Agar Gel / Q000379:methods; D004720:Endonucleases / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013737:Testis / Q000378:metabolism
chemical_list: D002457:Cell Extracts; D004720:Endonucleases; D011088:DNA Ligases