Expression ofMeis1,Hoxa7,andHoxa9in BM cells from sick ND13 and ND13-Meis1 mice. Expression of Meis1 transcripts (A), endogenous Meis1 (B), and Hoxa7 and Hoxa9 (C) in BM cells harvested from sick mice or transduced cells grown in LC. Mean expression shown for ND13 (n = 5), ND13-Meis1 (n = 5), sick mice, and control mouse (n = 1). LC samples consisted of transduced BM cells isolated by FACS and cultured for more than 28 days in 15% FBS, IL-3, hIL-6, and mSF (n = 1 for GFP⁺ control and ND13-Meis1 [ND/M] and n = 2 for ND13). For semiquantitative RT-PCR, all expression was normalized to GAPDH and then relative to control marrow, which was set at an arbitrary value of 1, except for the expression of endogenous Meis1 in the LC samples, which is given relative to GFP⁺ control. See “Materials and methods” for details. Endogenous Meis1-specific primers were designed not to amplify retrovirally driven Meis1 transcript. Mean ± SD shown. Similar analysis carried out for Hoxd13 was negative for expression (data not shown).