FIGURE 3.

Quantification of ATMdexa1 and full-length ATM versus ATMdexa1, by quantitative real time PCR. A, ATMdexa1 transcript was quantified in wild type and AT lymphoblastoid cells receiving 100 nm dexa with respect to untreated LCLs. In AT samples, the drug treatment leads to ATMdexa1 overexpression, whereas WT resulted in minimal or negative affect by the drug. AT cells are more sensitive to dexa exposure, ranging from 4- to 35-fold change overexpression. (p < 0.05 Wilcoxon matched pairs test n = 6). B, raw data from full-length ATM and ATMdexa1 mRNA quantification were compared by box and whiskers plot. Target amounts are reported in Log₁₀ ^ΔCT (HPRT1 as housekeeping gene). Although the amount of ATMdexa1 resulted in marked increase only in treated AT LCLs (p < 0.05 Wilcoxon matched pairs test), the full-length mRNA was unaffected by dexa (p < 0.05 Wilcoxon matched pairs test n = 6). Based on these results, ATMdexa1 formation is independent of full-length ATM mRNA synthesis, suggesting that the alternative spliced ATMdexa1 variant is directly prompted by dexa. atmFL, full-Length ATM; atmXA1, ATMdexa1. Error bars indicate mean ± S.D.