Competitive hematopoietic reconstitution with Zfp36l2 WT and KO fetal liver cells. A total of 5 × 105 donor-derived fetal liver cells (CD45.2+) from WT (n = 19) and KO (n = 23) E14.5 embryos were mixed with 5 × 105 adult bone marrow recipient–derived cells from B6.BoyJ (CD45.1+) mice and were injected into lethally irradiated B6.BoyJ (CD45.1+) mice. The percentage of donor CD45.2+ cells that engrafted, as determined by CD45.1/CD45.2 staining of peripheral blood, was examined at 1, 2, and 6 months after transplantation. Values are mean ± SD. Statistical significance was determined using the Student t test: ****P < .001.