DNA repair and human disease

DNA excision repair in spontaneously diabetic BB Wistar rats

BB Wistar rats develop a syndrome characterized by spontaneous diabetes mellitus as well as a wide variety of autoimmune, neoplastic, and degenerative disorders which do not occur in the outbred Wistar strain from which they were derived. This syndrome also includes elements of premature ageing (i.e., a markedly shortened lifespan and premature occurrence of diseases associated with ageing). Excision DNA repair capacity which has been reported to be directly proportional to maximal achievable life span was estimated in neonatal BB Wistar and outbred Wistar rats. Excision repair was assayed autoradiographically by determining unscheduled DNA synthesis following UV radiation of passage 3 cultured skin fibroblasts. No difference in excision repair capacity could be demonstrated between the two strains.

Quantification of unscheduled DNA synthesis in mononuclear leukocytes of the horse

This study compares the relationship between N-acetoxy-2-acetylaminofluorene (NA-AAF) and u.v. induced unscheduled DNA synthesis (UDS) and their respective relationships to age and blood pressure in horse mononuclear leukocytes with earlier, similar investigations on human leukocytes. U.v. induced UDS was found to proceed more rapidly than NA-AAF induced UDS. A pronounced lag period associated with the rapid demand for 3H-dThd into DNA after u.v. damage was observed. NA-AAF induced UDS correlated significantly with NA-AAF binding, age and the blood pressure of male horses. UDS values, induced by either method, were about half the level calculated for human leukocytes.

DNA polymerases alpha beta and gamma in inherited diseases affecting DNA repair

Fibroblasts derived from patients with diseases affecting DNA repair processes, such as Xeroderma Pigmentosum (classical and variant), Fanconi's anemia, Bloom's syndrome, Ataxia Telangiectasica, Progeria and Werner's syndrome, were assayed for the three DNA polymerases. The specific activities of these enzymes were found within the limits observed in normal human fibroblasts. Also the sedimentation properties of the three polymerases were unaltered.