The loss of the HECT domain of Ubr5 leads to decreased numbers of mature B cells within the BM. (A) Bar graph of the total number of cells per femur. (B) Bar graph of the frequency of B220⁺ cells in the BM. (C) Representative flow cytometry plot of total B220⁺ in the BM. (D) Bar graphs of B-cell populations gated on B220⁺ cells for pro- and pre-B cells (B220⁺IgM⁻IgD⁻), immature B cells (B220⁺IgM^loIgD⁻), transitional B cells (B220⁺IgM⁺IgD⁻), early mature B cells (B220⁺IgM⁺IgD⁺), and late mature B cells (B220⁺IgM⁻IgD⁺). (E) Representative flow cytometry plots for populations shown in panel D. (F) Absolute number of B-cell populations from panel D. (G) Bar graph of the population breakdown shown in panel H. (H) Representative flow cytometry plots gated for pro- and pre-B cells (B220⁺IgM⁻), immature B cells (B220⁺IgM^lo), and recirculating B cells (B220⁺IgM⁺) (top). A representative flow cytometry plot gated on B220⁺ cells gating for pro-B cells (B220⁺IgM⁻c-kit⁺) (middle) and pre-B cells (B220⁺IgM⁻CD25⁺) (bottom). (I) Absolute number of B-cell populations from G (N = 10). *P < .05, **P < .01, ***P < .001.