title: Fluoropyrimidine-mediated changes in small nuclear RNA.
abstract: Studies were completed to examine the effects of the antineoplastic agent 5-Fluorouridine (FUrd) on the metabolism of the small molecular weight nuclear RNA (snRNA). Cultured Sarcoma-180 murine tumor cells were exposed to FUrd concurrent with [3H]cytidine for 6 h, the drug was removed, and the RNA was isolated at 0, 24, or 48 h following the drug treatment. The results of these studies demonstrated that FUrd produced three dose-dependent changes in snRNA metabolism. The electrophoretic migration of the U4 and U6 snRNA was altered in nondenaturing 10% polyacrylamide slab gels. These results were not observed in denaturing gels or when RNA was extracted at temperatures exceeding 25 degrees C, suggesting that the incorporation of 5-fluorouracil induced secondary structural changes in these RNA. A dose- and time-dependent selective reduction in the turnover of the U1 snRNA synthesized in the presence of FUrd was observed as well, with levels over 100% higher than control cells at 48 h after exposure to 10 microM FUrd. These changes in snRNA metabolism may contribute to the reported alterations in large molecular weight RNA metabolism that also result in fluoropyrimidine-treated cells, or to cytotoxicity.
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003562:Cytidine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D009690:Nucleic Acid Conformation / Q000187:drug effects; D012342:RNA, Small Nuclear / Q000378:metabolism*; D012510:Sarcoma 180 / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014529:Uridine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D012342:RNA, Small Nuclear; C001943:5-fluorouridine; D003562:Cytidine; D014529:Uridine