Decay of bcl2 mRNA in extracts of CLL and normal B cells. The 5′-capped and polyadenylated [³²P]bcl-2–CR RNA and [³²P]bcl-2–CR-ARE RNA were incubated with S100 extracts prepared from either CLL cells from 4 patients or normal B cells from 3 human volunteers. At the indicated times, aliquots of the reaction mixtures were removed and analyzed by polyacrylamide gel electrophoresis and filmless phosphorimaging. The results are expressed as the mean percentage of full-length RNA remaining ± SEM as a function of time. ○ indicates CLL cell extract + [³²P]bcl-2–CR RNA; •, CLL cell extract + [³²P]bcl-2–CR-ARE RNA; □, normal B-cell extract + [³²P]bcl-2–CR RNA; ▪, normal B-cell extract + [³²P]bcl-2–CR-ARE RNA; ▴, normal B-cell extract + [³²P]bcl-2–CR-ARE RNA + 280 nM purified recombinant nucleolin.