Figure 5.

 Increased transcription of p21^waf1 and mdm2 correlates with IR-induced post-translational modification of p53. (A) Northern blot analysis of SY5Y RNA. Total RNA isolated from SY5Y cells that had been either untreated (control, C) or treated with 1 or 2 Gy IR or treated with 20 μm ALLN (A) was assayed for hybridization to ³²P-labeled p21^waf1 cDNA (top), ³²P-labeled mdm2 cDNA (middle), or ³²P-labeled GAPDH cDNA (bottom) coding sequence probes. (B) Northern blot analysis of ML-1 RNA. Total RNA was isolated from ML-1 cells that were either untreated (C) or treated with 5 Gy IR (+IR), 5 Gy IR + 20 μm ALLN (IR + A), or 20 μm ALLN (A). The nitrocellulose was sequentially assayed for hybridization to p21, mdm2, and gadph-labeled cDNA probes (top, middle, and bottom, respectively).