PEAR1 expression in differentiating human CD34⁺ cells. (A) Immunohistochemical staining of PEAR1 in human bone marrow sections, at 630- and 1000-fold magnification; MKs (white asterisk), myeloid precursors (orange arrows), and erythroid precursors (red arrows) are indicated. (B) Western blot for PEAR1 in red blood cell lysates (RBC), platelets, and peripheral blood mononuclear cells (PBMC) vs GAPDH control. (C) PEAR1, ITGA2B (CD41), and hypoxanthine guanine phosphoribosyl transferase expression on day 0, day 6, and day 12 in CD34⁺ cells by qRT-PCR vs GAPDH control and by RT-PCR vs ACTB (β-actin) control. (D) Flow cytometric measurement of PEAR1 on the membrane in 10-day-old CD34⁺ cell cultures after staining with immunoglobulin G control (MFI 562) and PEAR1-Ab (MFI 1287), as indicated (representative for n = 3); western blot for PEAR1 in CD34⁺ cell lysates, at days 6 and 10, with HDAC-1 as loading control. 1 A.U., 1 copy for 10⁵ copies of housekeeping gene.