Human bone marrow CD34⁺ cells expand at a higher rate when treated with TAT-SALL4B protein. (A) Bright field images of CD34⁺ cells after 3 days of protein treatment (10×). (B) Fold increase and total cell number (C) of TAT-SALL4B–treated bone marrow cells versus control cells treated solely with BSA. (D) Number of CFU colonies formed from hematopoietic stem cells treated with TAT-SALL4B protein compared with unmanipulated CD34⁺ cells. (E) Types of CFU colonies formed after treatment with TAT-SALL4B protein.