R4 RGS inhibit early HSPC engraftment. Control or RGS-overexpressing CD34⁺ cells were intravenously infused into sublethally irradiated NOD/SCID mice. (A) Representative flow cytometry plots showing the identification of engrafted human hematopoietic cells in the murine BM. Human CD45⁺ cells in the recipient BM (B) and spleens (C) were enumerated by flow cytometry at 8 weeks after transplantation. Each data point represents the average engraftment level of 2 animals in a single experiment, with 8 to 9 independent experiments performed (ie, 16-18 animals/group). Statistics: 2-tailed, paired Student t test. P values are indicated.