eGFP expression in tissues. eGFP expression was assessed in bone marrow, spleen, blood (A), and thymus (B) from recipients of LeGFPSN-transduced, MNDeGFPSN-transduced, and LN-transduced (data not shown) bone marrow 2 weeks, 8 to 12 weeks, 4 to 5 months, and 6 to 8 months after BMT. Values are given as the mean ± standard error of the mean. n is the number of animals analyzed for each time point and vector. * and ** mark differences in the percentage of expression between MNDeGFPSN and LeGFPSN that are statistically significant (*P < .05; **P < .005).