DNA-Synthesehemmung durch 5-FUDR bei Sinapis alba (L.) / Inhibition of DNA-Synthesis by 5-FUDR in Sinapis alba (L.)

Abstract

In Sinapis alba seedlings the cell elongation is inhibited by 5-FUDR. At a concentration of 10-5ᴍ FUDR reduces the incorporation of 3H-cytidine into the DNA of the hypocotyl by 50% in 24 hours; if, however, the labeling begins two hours after application of FUDR the inhibition amounts to 63 per cent. In the cotyledons the corresponding values are 73 and 79 per cent. On the contrary, FUDR enhances the incorporation of 14C-thymidine into DNA by 48% and 44% in the hypocotyl and cotyledons, respectively. These experiments suggest that FUDR inhibits DNA synthesis by blocking the thymidine pool (or thymidine-5-phosphate pool)