Fig. 7. Induction of p21waf-1 mRNA transcription in HeLa cells and revertants after {gamma}-irradiation. Total mRNA (15 µg) from HeLa, HA, and HF exposed to 0 or 5 Gy of {gamma}-irradiation were separated in agarose gel containing formaldehyde, transferred to nylon membranes, and hybridized to [32P]dCTP-labeled p21waf-1 cDNA probe. B, ethidium bromide staining of the Northern blot.