tailieunhanh - Báo cáo khoa học: Nucleotide excision repair rates in rat tissues

We have determined and compared nucleotide excision repair capability of several rat tissues by amethod based on restoration of the transformation activity of UV-irradiated pBlueScript by incubation in repair-competent protein 3 hof incubation, plasmidDNAwas isolated and used to transform competent Escherichia colicells. Damaged plasmids showed low transformation efficiency prior to incubation in repair-competent extracts. After incubation the transformation efficiency was restored to different extents permitting calculationof the repair capacity of the extracts | Eur. J. Biochem. 270 1000-1005 2003 FEBS 2003 doi Nucleotide excision repair rates in rat tissues Anastas Gospodinov Rumen Ivanov Boyka Anachkova and George Russev Institute of Molecular Biology Bulgarian Academy of Sciences Sofia Bulgaria 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 hepa-tectomy and mitogen stimulation their repair capability increased in parallel with the respective proliferative rates. Keywords DNA repair DNA replication protein extract rat tissues UV irradiation. DNA repair and particularly nucleotide excision repair NER is one of the primary pathways by which mammalian cells remove a wide variety of DNA lesions. In the process of repair the products of more than a dozen genes are involved in damage recognition incision elongation and ligation of DNA to collectively restore its original structure 1-3 . Many other cellular factors normally participating in transcription and replication also play a role in the process of DNA repair 4-6 . The NER pathway can recognize a broad spectrum of helix-distorting lesions such as UV-induced pyrimidine dimers bulky adducts cross-links etc. and remove them by excision