Verification of array results. (A) Northern blot and qRT-PCR. RNA from Hoxa9/Meis1-transduced MLL-ENL-ERtm cells was isolated 72 hours after inactivation of MLL-ENL and compared with control RNA from cells transduced with empty vectors. Hybridization was done with c-Myb- and β-Actin-specific probes. Specific bands are labeled. qRT-PCR was performed with an intron-spanning primer pair, and expression levels were determined with the ΔΔCt method normalizing to actin. Means and standard deviations of triplicates are given. c-Myb RNA concentration in control cells was arbitrarily set to 1. (B) qRT-PCR testing for changes in Meis1, Hoxa9, and c-Myb expression in MLL-ENL-ERtm cells after inactivation of MLL-ENL. RNA was isolated from cells in the presence of 4-OHT (0-hour value, ▪), and 96 hours after 4-OHT withdrawal (□). The experiment was conducted as before except that 0-hour expression values were set arbitrarily to 1.
