CD34⁺ cells' expression of mRNA for P2XRs and P2YRs and Western blot analysis for P2X₇R and P2Y₁R. P2XR (A) and P2YR (B) subtypes were expressed by HSCs. RT-PCR and Western blot were performed as described in “Materials and methods”: P2X₁ (248 bp), P2X₂ (355 bp), P2X₃ (437 bp), P2X₄ (521 bp), P2X₅ (614 bp), P2X₆ (520 bp), P2X₇ (399 bp), P2Y₁ (260 bp), P2Y₂ (367 bp), P2Y₄ (433 bp), P2Y₆ (459 bp), P2Y₁₁ (238 bp). The expression of P2X₇ and P2Y₁ was confirmed, at the protein level, in panels C and D, respectively. MW indicates molecular weight marker; HSC, hematopoietic stem cells; Fibr, human fibroblasts; DC, human monocyte-derived dendritic cells; HEK293-P2X₇, human embryonic kidney cells expressing P2X₇R.