Expression of c-mpl-P and c-mpl-K RNA by real-time RT-PCR in platelets and MKs from normal adult controls, newborns, and TAR syndrome patients.

Expression of c-mpl-P, c-mpl-K, GPIIb, and 18S was studied by a quantitative RT-PCR assay (see “Materials and Methods”). (A) Comparison of the expression of c-mpl-P in normal adults and TAR platelets. Expression of c-mpl-P was normalized in each sample to the expression of GPIIb. This is expressed by a ratio that does not correspond to the real ratio between the 2 different transcripts because we did not use a standard. This ratio allows the comparison of the c-mpl-P transcript expression in normal and TAR platelets. (B) Ratio between c-mpl-P and c-mpl-K in platelets. To calculate the real ratio between the 2 isoforms, a standard was constructed that contains the 2 amplified sequences permitting precise evaluation of the efficiency of each PCR. (C) Ratio between c-mpl-P and c-mpl-K in MKs. MKs were obtained from culture of normal adult bone marrow at day 7 and day 12, from cord blood (NN) at day 12, and TAR patients at day 12.