C/EBP induces transcription of the endogenous PU.1 gene in the absence of protein synthesis. (A) Total cellular RNAs were prepared from 32D-Puro, 32D-WT-ER-1, Ba/F3(G), and Ba/F3(G)-WT-ER cells proliferating in IL-3 with estradiol for 0 hours, 4 hours, 8 hours, 1 day, 2 days, 3 days, or 4 days. These RNAs were then subjected to Northern blotting for PU.1 and 18S RNAs. (B) The Northern blot described in Fig 2 was probed also for PU.1 RNA. The 18S RNA levels shown in Fig 2 are again shown (top panels). Total cellular RNAs were also prepared from Ba/F3(G)-WT-ER cells cultured in IL-3 with estradiol for 0 or 8 hours, from a third culture exposed to CHX for 8 hours, and from a fourth culture exposed to CHX for 30 minutes followed by CHX with estradiol for 8 hours. These RNAs were subjected to Northern blotting for PU.1 and 18S RNAs (bottom panels).