IN-VITRO SPLICING OF PREMESSENGER RNA WITH EXTRACTS FROM 5-FLUOROURIDINE-TREATED CELLS

The effect of 5-fluorouridine (5-FU) treatment of cells on the splicin g of pre-mRNA was determined using cellular extracts and splicing vitr o. Nuclear extracts from control cells and cells treated with 5-FU wer e prepared and used to splice pre-mRNAs in vitro. The drug treatment r esulted in inhibition of cell growth but had little effect on RNA synt hesis. The extracts from 5-FU-treated cells showed significant inhibit ion of splicing. This inhibition was the result of reduced efficiency and was not caused by a block at a specific step in the splicing pathw ay. There were no observable changes in the levels or physical propert ies of the small nuclear ribonucleoprotein particles that are essentia l co-factors in the splicing process. The deficiency in splicing in th e extracts from 5-FU-treated cells could be supplemented by the additi on of complementary fractions from a control extract.