ENDOGENOUS ACTIVATION OF PREMUTAGENS BY L5178Y CELLS

THE LONG-TERM OBJECTIVE OF THIS PROJECT IS TO GENERATE A MAMMALIAN CELL LINE THAT ENDOGENOUSLY EXPRESSES METABOLICALLY ACTIVE PROSTAGLANDIN H (PGH) SYNTHASE, A PEROXIDASE ENZYME KNOWN TO BE INVOLVED IN MUTAGEN ACTIVATION. AVAILABILITY OF SUCH A CELL LINE WOULD OVERCOMELIMITATIONS OF CURRENT MUTAGENESIS TESTING METHODS AND LEAD TO RESULTS MORE APPLICABLE TO HUMAN RISK ASSESSMENT. TRANSFECTION OF THE MOUSE LYMPHOMA CELL LINE L5178Y/TK(+/-),A CELL LINE SUITABLE FOR USE IN MUTAGENESIS TESTS, WITH AN AVAILABLE CDNA CLONE CONTAINING THE PGH SYNTHASE GENE WILL BE USED TO GENERATE A STABLY TRANSFECTED CELL LINE POSSESSING THE CHARACTERISTICS DESIRED. IT IS EXPECTED THAT PHASE I OF THIS PROJECT WILL RESULT IN THE PRODUCTION OF A CELL LINE THAT EXPRESSES STABLE AND FUNCTIONALLY ACTIVE PGH SYNTHASE. LOGICAL DEVELOPMENTS FOR PHASE II WORK INCLUDE: (1) SUBCELLULAR LOCALIZATION OF THE EXPRESSED PGH SYNTHASE IN THE TRANSFECTED LYMPHOMA CELLS, AND (2) SCREENING OF CHEMICALS THAT MAY REQUIRE PEROXIDASE ACTIVATION TO EXHIBIT THEIR MUTAGENICITY.