Table 1.

Effect of γ irradiation on the expression of various DNA damage-inducible genes

Cell lineHTLV-IFold increase in relative mRNAa
MDM2Gadd45p21waf1/cip1Bax
ML-14.85.27.76.7
C81+1.21.51.91.7
Hut102+1.11.01.00.4
MT-2+2.11.72.21.0
  • a Relative signals for the Northern blot analyses were quantitated by using a PhosphorImager and the ImageQuant program. Values represent the ratio of the signal in the γ-irradiated samples compared with untreated controls. Briefly, exponentially growing cells were γ-irradiated with 20 Gy and incubated for 4 h, at which time poly(A) mRNA was prepared, electrophoresed, and blotted to a Nytran membrane (Schleicher & Schuell). The blots were then sequentially probed with the following cDNA probes: MDM-FL4, a full-length MDM2 clone (39); pHulB2, a human Gadd45 clone (42); pZL-Waf1, a full-length Waf1 cDNA clone (18); and pBAX N7, a full-length human Bax cDNA clone (8). The MDM2 and p21 probes were kindly provided by Bert Vogelstein (Johns Hopkins Oncology Center, Baltimore, Md.). The Gadd45 and Bax probes were a kind gift from Albert J. Fornace, Jr. (National Institutes of Health, Bethesda, Md.).