Semiquantitative RT-PCR analysis of −245 hPF4/lacZ expression in bone marrow RNA. Increasing amounts of total input RNA (50, 100, and 200 ng) from bone marrow of transgenic (F₀no. 16 and F₀ no. 3) and wild-type (WT) mice were reverse transcribed and amplified for 25 cycles. The PCR products for the −245 hPF4/lacZ (164 bp) and GAPDH primers (392 bp13) were visualized by ethidium bromide staining with 2% agarose gels.