STI571 does not reduce expression of SHIP RNA or protein in expanded clones of BCR-ABL–transduced +/+ cells. (A) Top panel shows real-time RT-PCR SYBR Green1 fluorescence versus cycle number of murine SHIP and GAPDH cDNAs prepared from RNAisolated from BCR-ABL–transduced +/+ cells cultured with 0 to 10 μm STI571 for 16 hours. Bottom panel shows the calculated levels of SHIP transcripts (after normalization to GAPDH transcript levels in the same extracts) in each treated clone expressed as a percentage of the SHIP transcript levels in the untreated control. The levels of SHIP transcripts relative to GAPDH in each sample were calculated using the formula described.²⁶  (B) Western analysis of cells from a BCR-ABL–transduced +/+ clone (no. 1) cultured with varying concentrations of STI571 as described in panelA. Antibodies were the same as in panel B of Figure 7.