Myosin expression during normal and pathologic MK differentiation. (A) CD41⁺ MKs were derived from adult blood CD34⁺ cells and studied at 3 different days (D6 to D14 corresponding to cells with increasing maturity). MYL9, MYL6, MYL12A and MYL12B mRNA level were determined by real time RT-PCR. The histograms show 1 representative experiment of 2, each in triplicate. Error bars represent ± SD of triplicate. (B) Expression analysis of MYH9, MYH10, MYL9, MYL12A, and MYL12B genes in MKs of FPD/AML patients. CD34⁺ cells isolated from peripheral blood of 6 patients (P: AII-1, AII-2, BII-2, BII-3, DIII-1, and DIII-3) and 4 healthy individuals (C) were grown in liquid medium in presence of TPO, IL3, IL6, SCF, and FLT3-L. At day 10 of culture, mature (CD41⁺CD42⁺) MKs were sorted and mRNA level was analyzed by real time RT-PCR. Expression was compared with control C1. (*P < .05, **P < .01, ± SEM 2-tailed welch corrected). (C) MYH9 and MYH10 mRNA levels were detected by real time RT-PCR. (A-C) Real time RT-PCR was normalized to PPIA and HPRT. As similar results were obtained, only results normalized to PPIA are shown. (D) MYH9 and MYH10 proteins were detected by immunofluorescence labeling using antibodies against human MYH10, MYH9 (red), and von Willebrand Factor (VWF, green). Nucleus was stained with DAPI (blue).