RODENT COMPLEMENTATION GROUP-8 (ERCC8) CORRESPONDS TO COCKAYNE-SYNDROME COMPLEMENTATION GROUP-A

US31 is a W-sensitive mutant cell line (rodent complementation group 8 ) derived from a mouse T cell line L5178Y, We analyzed removal kinetic s for UV-induced cyclobutane pyrimidine dimers and (6-4) photoproducts in US31 cells using monoclonal antibodies against these photoproducts . While nearly all (6-4) photoproducts were repaired within 6 h after UV-irradiation, more than 70% of cyclobutane pyrimidine dimers remaine d unrepaired even 24 h after UV-irradiation. These kinetics resembled those of Cockayne syndrome (CS)cells, Since US31 cells had a low effic iency of cell fusion and transfection, which hampered both complementa tion tests and gene cloning, we constructed fibroblastic complementati on group 8 cell line 6L1030 by fusion of US31 cells with X-irradiated normal mouse fibroblastic LTA cells. Complementation tests by cell fus ion and transfection using 6L1030 cells revealed that rodent complemen tation group 8 corresponded to CS complementation group A.