FACS analyses for FLAG expression in BM and PB of rat no. 14. Rats were injected intrafemorally with SV(Nef-FLAG), or SV(BUGT) as a control, as in Figure 4 legend. PB and BM cells were obtained 22 weeks later and immunostained for FLAG or FLAG⁺ granulocytes as in Figure 5 legend. Shown are the comparative percentages of total cells positive for FLAG in the unfractionated population and in the granulocyte population, with background values (from SV(BUGT) recipients) subtracted.