PCR amplification of FXI exons 3-6, GPIIb, and CD-18 using RT RNA from human platelets, bone marrow, and leukocytes. PCR was performed as described in the Materials and Methods section. Lanes 1, bone marrow; 2, 293 cells transfected with wild-type FXI cDNA; 3, fresh platelets; 4, platelets from platelet-pheresis; 5, granulocytes; 6, mononuclear leukocytes. MWM indicates a 100 bp DNA ladder that serves as molecular weight markers. The intense marker band is 500 bp in size.