Fig. 6.
Expression profiles for B lineage genes and intracellular proteins in pro-B and pre-B subpopulations.
(A) Human CD34+CD19+VpreB−pro-B, CD19+ κ/λLC−VpreB+pre-B, and CD19+κ/λLC−CD34−VpreB−pre-B cells were isolated from fetal bone marrow samples. (B) Mouse CD19+ VpreB+ and CD19+VpreB− pro-B cells were isolated from RAG2−/− bone marrow, and VpreB+ and VpreB− subpopulations of pre-B cells (CD19+BP-1+ κ/λLC−) were isolated from bone marrow of wild-type juvenile mice. Subpopulations were purified by 2 rounds of immunofluorescence-based sorting, and the sorted cells were used as templates for RT-PCR assays. PCR products were visualized on agarose gels by ethidium bromide staining. (C) Analysis of cytoplasmic VpreB, Igβ, and conventional LC protein expression within pre-BCR− pre-B cells. Dashed lines indicate staining of pre-BCR− cells. Solid lines represent staining in control pre-BCR+ cells (i) and CD19+κ/λLC+ B cells (ii) and (iii). Background staining with isotype-matched antibodies of irrelevant specificity is indicated by shaded histograms.