Termination of RNA by nucleotides of 9-β-D-xylofuranosyladenine

Incubation of CHO cells with 21 μM [³H]9-β-D-xylofuranosyladenine for 2 hr resulted in the intracellular accumulation of 9-β-D-xylofuranosyladenine 5′-triphosphate and the incorporation of radioactivity into HC1O₄ -insoluble material. After incubation of the HC1O₄ -insoluble material in 0.3 N KOH for 16 hr, the radioactivity associated with the nucleoside fraction coeluted with authentic 9-β-D-xylofuranosyladenine by high-pressure liquid chromatography and was resistant to oxidation with NaIO₄. Upon incubation with adenosine deaminase (E.C. 3.5.4.4.), the radioactivity coeluted with xylosylhypoxanthine. The data suggest that termination of RNA chains by xylosyl nucleotides may be a mechanism for producing the toxicity of 9-β-D-xylofuranosyladenine.