Overexpression of cyclin D2 in hematopoietic progenitor cells rescues mice from lethal myeloablation. Two thousand LSK cells transduced with control- or cyclin D2–containing vector were transplanted without any support cells into lethally ablated (975 cGy) adult recipients. A total of 42, 14, and 28 mice were transplanted in control-transduced, control-transduced + G-CSF–treated, and cyclin D2–transduced groups, respectively. From day 1 after transplantation, PBS (control transduced) or 100 μg/kg rhG-CSF was subcutaneously injected every other day for a total of 7 times. Twenty-eight mice served as nontransplantation controls.