Agarose gel electrophoresis of RT-PCR products stained with ethidium bromide.

(1) DNA ladder. (2) RT control. (3) Human liver mRNA. (4) mRNA from NK cells simulated with IL-2. (5) Negative control, NK mRNA, RT omitted. (6) Negative control, NK mRNA, Taq polymerase omitted. (7) Negative control, NK mRNA omitted. The 2 products seen with human liver mRNA correspond to a 1300-bp band derived from the transferrin receptor and a 270-bp band from TPO. NK mRNA gave a single product derived from the transferrin receptor but no TPO-derived product.