(A) Whole BM from 10 wild-type mice was pooled and fractionated by
FACS into HSCs (Lin–Sca-1hic-kithi;
Lin: CD3ε, CD4, CD8a, CD19, Ly6G, CD45R), granulocyte-macrophage
progenitors (GMP:
Lin–Sca-1–c-kit+CD34+FcRγII/IIIhi),
common myeloid progenitors (CMP:
Lin–Sca-1–c-kit+CD34+FcRγII/IIIlo),
megakaryocytic erythroid progenitors (MEP:
Lin–Sca-1–c-kit+CD34–FcRγII/IIIlo),
or a progenitor mix (CMP, GMP, MEP, CLP:
Lin–Sca-1–c-kitlo/–).
Epcr and Gapdh mRNA were amplified by 35- and
30-cycle RT-PCR, respectively, from RNA isolated from sorted cell pools.
(B) Detection of EPCR expression in wild-type splenocytes.
Back-gating of EPCR-positive cells (gate P1, gray line indicates signal obtained
with isotype control antibody) shows EPCR expression in
CD11chiPDCA-1– DCs (red). (C)
Abundance of EPCR-expressing CD11chiPDCA-1– DCs
is diminished in EPCRlo mice. Spleen DCs were enriched by capture on
CD11c/PDCA-1 magnetic beads and analyzed for EPCR expression as in B.
(D) Detection of EPCR surface expression captures the majority of
DCs expressing Epcr mRNA. Spleen DCs were enriched on magnetic
beads as in C, and EPCR+ cells were isolated by FACS via
gating on CD11chiPDCA-1– DCs, followed by
sorting into EPCR+ and EPCR–
CD11chiPDCA-1– cells (left panel, solid gray
line: isotype control on post-sort EPCR+ cells; dotted red line: FITC
intensity of post-sort EPCR-depleted
CD11chiPDCA-1– cells; solid red line: FITC
intensity of post-sort EPCR+
CD11chiPDCA-1– cells). Quantitative RT-PCR
analysis of Epcr mRNA on sorted cells shows depletion of
Epcr mRNA in cells lacking EPCR surface expression as detected
by flow cytometry (right panel; bars indicate the average ± SD of the
detection threshold expressed as the ΔCT value for
Epcr mRNA determined in 2 independent sorting experiments,
with 3 measurements/sample).