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Induction of Cell Killing, Mutation and umu Gene Expression by 6‐Mercaptopurine or 2‐Thiouracil with UVA Irradiation
Author(s) -
Komeda Kazuko,
Iwamoto Sakae,
Kominami Seiji,
Ohnishi Takeo
Publication year - 1997
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1997.tb01885.x
Subject(s) - mercaptopurine , thiouracil , mutation , gene expression , gene , chemistry , genetics , biology , microbiology and biotechnology , pharmacology , thyroid
— When Escherichia coli cells were irradiated by UVA in the presence of 6‐mercaptopurine (6‐MP) or 2‐thiouracil (S 2 Ura), two kinds of repair‐deficient strains of recA − and uvrA − were killed more efficiently than the parental wild‐type strain having normal repair capacities. In addition, these agents with UVA exposure greatly induced the incidence of mutations in the uvrA − strain as compared with the wild‐type strain but not the uvrA − strain. Furthermore, the induction of expression of umuDC genes was investigated in two Salmonella typhimurium strains, TA1S35 and TA1538, carrying a pSK1002 plasmid. In these systems, it is easy to measure β‐galactosidase activities for the induced activities of SOS responses. These agents with UVA exposure also induced expression of the umuDC genes. These results suggest that 6‐MP and S 2 Ura with UVA induce DNA damage which is repairable by the excision repair mechanism.