Nucleotide excision repair rates in rat tissues

We have determined and compared nucleotide excision repair capability of several rat tissues by a method based on restoration of the transformation activity of UV-irradiated pBlueScript by incubation in repair-competent protein extracts. After 3 h of incubation, plasmid DNA was isolated and used to transform competent Escherichia coli cells. Damaged plasmids showed low transformation efficiency prior to incubation in repair-competent extracts. After incubation the transformation efficiency was restored to different extents permitting calculation of the repair capacity of the extracts. Our results showed that rapidly proliferating tissues such as liver, kidney and testis showed higher nucleotide excision repair capacity than slowly proliferating tissues such as heart, muscle, lung and spleen. When liver and splenocytes were stimulated to proliferation by partial hepatectomy and mitogen stimulation, their repair capability increased in parallel with the respective proliferative rates.