Supplementary Figure 1: Characterization of Bcl11b deletion systems in vivo.

(a), Phenotypic timing of the activity of Lck-Cre (Lck-Cre^cw) in vivo based on activation of ROSA26R-YFP. For each Bcl11b genotype characterized in (a) and (b), results are representative of the following numbers of animals: WT, N=5; HE, N=6; KO, N=6. (b), Most CD25⁺ thymocytes in mice with Bcl11b deleted by Lck-Cre have the c-Kit^hi+ phenotype of normal DN2a cells but the YFP⁺CD44^low phenotype similar to normal DN2b/DN3a cells. (c), (Left) Bcl11b deletion in vivo severely reduces thymocyte cellularity whether deleted before commitment by Vav1-iCre or after commitment by Lck-Cre. WT, HE, and KO refer to Bcl11b genotypes in the indicated Cre backgrounds: Bcl11b^+/+, Bcl11b^+/fl, and Bcl11b^fl/fl, respectively. Each symbol represents a different animal and the short bars indicate geometric means. N of individual animals counted for each genotype: Vav1-iCre WT N=3; Vav1-iCre HE N=10; Vav1-iCre KO N=12; Lck-Cre WT N=8; Lck-Cre HE N=5; Lck-Cre KO N=7. (Right) Representative photographs of thymuses from age-matched Lck-Cre;ROSA26R-YFP mice with Bcl11b^+/+ (WT), Bcl11b ^fl/+ (HE), and Bcl11b^fl/fl (KO) genotypes at the Bcl11b locus.