Supplementary Figure 6: The B cell developmental arrest caused by ZIP7 deficiency is not associated with endoplasmic reticulum (ER) stress and is not corrected by expression of the pro-survival factor BCL2.

(a) RT-PCR assay for the ER-stress-associated shortened Xbp1-splice variant (Xbp1s). Results show RT-PCR of cDNA from WT (lanes 1–3) or P198A-Hom (lanes 4–6) flow-sorted B cells from FrD and FrE. The controls were tunicamycin treated (Tm) or untreated (Un) mouse embryonic fibroblasts (MEFs). Three mice were studied per genotype in the single experiment shown. (b-c) Representative flow cytometry analysis of B cell development and maturation in BM (b) and spleen (c) of WT and P198A-Hom mice, with and without co-expression of a Bcl2 transgene (upper and lower panels). Gates corresponding to Fr A-F in the BM and total (B220⁺CD19⁺), follicular (Fo, CD23⁺CD21⁺) and Marginal Zone (MZ, CD23^-CD21^hi) B cells in the spleen are highlighted. (d-e) Absolute numbers of B cells, gated as in (b-c), in Hardy Fractions in the BM (d) and in splenic subsets (e) from WT, P198A-Hom, WT BCL2 transgenic (BCL2) and P198A-Hom BCL2 transgenic (P198A-Hom BCL2) mice, here n=3 per group and representative of 4 independent experiments. Bars show means and 95% CI; statistical comparison was by two-way ANOVA with Bonferroni correction for multiple comparison, * =p<0.0001.