Adult Tr4 heterozygous mutant mice exhibit impaired erythropoiesis. (A) Flow cytometric analysis of bone marrow cells recovered from 6- to 8-week-old WT and Tr4^+/− femurs stained with α-CD71 and α-TER119 antibodies. The percentage of cells within each gate is indicated on the flow plots. (B) The absolute number of cells within each gate was quantified in WT (closed circles) and Tr4^+/− (open circles) mice at each stage (II, III, and IV) of CD71/TER119-monitored erythroid differentiation.^32,33  (C) Flow cytometric analysis of total bone marrow cells from 6- to 8-week-old WT and Tr4^+/− femurs stained with α-CD44 vs FSC as another indication of erythroid differentiation (II-VI).⁵⁸  The percent of cells within each gate is shown on a representative flow plot. (D) The absolute number of cells in each gate. *P ≤ .05 as determined by Student t test comparing Tr4 heterozygous mutant with WT bone marrow cells.