Long-term monoclonal reconstitution of erythropoiesis in genetically anemic W /Wv mice by injection of 5-fluorouracil-treated bone marrow cells of Pgk -1 b / Pgk-1 a mice. Blood 70

The spleen colony-forming assay does not represent the number of hematopoietic stem cells with extensive self-maintaining capacity because five to 50 spleen colony-forming units (CFU-S) are necessary to rescue a genetically anemic (WB X C57BL / 6)F1- W/Wv(WBB6F1 W/WV) mouse. We investigated which is more important for the reconstitution of erythropoiesis. the transplantation of multiple CFU-S or that of a single stem cell with extensive self-maintaining potential. The electrophoretic pattern of hemoglobin was used as a marker of reconstitution and that of phosphoglycerate kinase (PGK). an X chromosome-linked enzyme. as a tool for estimating the number of stem cells. For this purpose. we developed the C57BL/6 con-geneic strain with the Pgk-1 gene. Bone marrow cells were harvested after injection of 5-fluorouracil fro