Figure 7

DMP1-Cre/Ai9 labeled cells express RANKL and contact B cells. (A) Flow cytometric analysis of RANKL expression in CD45⁺tdT⁺ parent population from bone marrow flush. (B) Bone marrow from femoral section stained with antibody to RANKL. Red–tdT, Green-RANKL, Blue-DAPI. White arrows—stromal cells double positive for RANKL and tdT. (C) Frozen histology section (20 μm) from femur of Dmp1-Cre/Ai9 animal stained for B220 and imaged by confocal microscopy. Z stack is shown. Red-tdT, Cyan-B220. (D) Confocal imaging of bone marrow demonstrates contacts between DMP1-Cre/Ai9 stromal cells and B cells (white arrows). Yellow arrow—tdT⁺ hematopoietic cell. Red-tdT, Cyan-B220, Blue-DAPI (E) Relative mRNA expression of IL7 from sorted tdT⁻ and tdT⁺ bone marrow cells. RNA from bone was used as positive control, representative experiment shown, n = 2.