Expression of GPIbβ, GPIIIa, and PF4 in megakaryocytes contained in individual EMk colonies from the early YS cells by RT-PCR.

Lanes 1, 2, and 3 showed 3 individual EMk colonies from 7.5-dpc YS. Erythrocytes pooled from 5 E bursts in the same culture were used as a negative control (lane 4), and adult BM cells were as a positive control (lane 5). G-CSFR expression was also examined to demonstrate the specificity of the PCR reactions.