c-mpl mRNA expression in murine LEC-1. RT-PCR was performed on 1 μg total RNA obtained from A12 and C7 LEC-1 clones. Reverse-transcription and amplification were performed as described in Materials and Methods with the primers specific for c-mpl. Constitutive expression for c-mpl was detected in both A12 and C7 LEC-1 clones. 1: Molecular markers; 2: negative control (PCR reaction without RNA template); 3: internal control, β-actin; 4: c-mpl.