Gene expression patterns upon increased STAT3β expression reveal SELL to be a potential STAT3β target. (A) Heatmap showing significantly up- (32 genes) or downregulated (38 genes) genes between murine wt and Stat3β^TG BM-derived Venus⁺ blasts (n = 3). (B) Normalized mRNA expression, displaying the upregulation of Sell in Venus⁺ Stat3β^TG blasts, is shown (top; n = 3 per group). Quantification of cell surface–bound SELL/CD62L in BM-derived Venus⁺ blasts, measured by flow cytometry (middle; n = 6 per group), and levels of soluble, shed SELL in plasma, assessed via enzyme-linked immunosorbent assay (bottom; n = 9 per group), demonstrate the upregulation of SELL on the cell surface of Stat3β^TG blasts and the difference in shed SELL present in PB. Data were compared using the Student t test. (C) Methylcellulose-based colony formation assays of wt and Stat3β^TG FLCs and BMCs, pretreated with or without a blocking antibody for SELL/CD62L (MEL-14), were analyzed by number of colonies upon 3 replatings (1 replating shown; n = 12 per group). Data were compared using 1-way analysis of variance. *P < .05, **P < .01, ***P < .001.