p210^BCR/ABL is expressed in p210-eGFP–transduced GFP⁺ CD34⁺ cells.

(A) p210-eGFP– or eGFP-transduced GFP⁺ CD34⁺cells were cytospun onto glass slides and fixed in 100% ethanol for 20 minutes. Endogenous peroxidase was blocked with 0.3% H₂O₂ in 50% methanol for 5 minutes. Immunohistochemistry was performed using an established avidin-biotin complex with specific primary anti-BCR antibody. Staining is significantly greater in the cytoplasm of p210-eGFP–transduced eGFP⁺ CD34⁺ cells (ii) than in eGFP-transduced eGFP⁺ CD34⁺ cells (i). Representative example of 2 individual experiments is shown. (B) Proteins were extracted from 5 × 10⁵ p210-eGFP– or eGFP-transduced GFP⁺CD34⁺ cells. Proteins were resolved by electrophoresis on 8% polyacrylamide gels and transferred to polyvinylidene difluoride. Blots were incubated with anti-ABL antibody and a goat antimouse horseradish peroxidase–conjugated antibody, as described in “Materials and methods.” Protein bands were visualized using an ECL detection system. p210^BCR/ABL was present in p210-eGFP– but not in eGFP-transduced eGFP⁺ CD34⁺ cells at levels similar to those of endogenous p145^ABL. Representative example of 2 individual experiments is shown.