PLURIPOTENT HEMATOPOIETIC STEM-CELLS CONTAIN HIGH-LEVELS OF MESSENGER-RNA FOR C-KIT, GATA-2, P45 NF-E2, AND C-MYB AND LOW-LEVELS OR NO MESSENGER-RNA FOR C-FMS AND THE RECEPTORS FOR GRANULOCYTE-COLONY-STIMULATING FACTOR AND INTERLEUKIN-5 AND INTERLEUKIN-7

Pluripotent hematopoietic stem cells (PHSCs) were highly enriched from mouse bone marrow by counterflow centrifugal elutriation, lineage sub traction, and fluorescence-activated cell sorting based on high c-kit receptor expression (C-kit(BR)). We used reverse transcriptase polymer ase chain reaction to assay the C-kit(BR) subset and the subsets expre ssing low (C-kit(DULL)) and no (c-kit(NEG)) c-kit receptor for express ion of mRNA encoding hematopoietic growth factor receptors and transcr iption factors. The c-kit(BR) cells had approximate to 3.5-fold more c -kit mRNA than unfractionated bone marrow cells, The C-kit(DULL) cells had 47-58% of the c-kit mRNA found in C-kit(BR) cells and the C-kit(N EG) cells had 4-9% of the c-kit mRNA present in C-kit(BR) cells, By co mparing mRNA levels in C-kit(BR) cells (enriched for PHSCs) with those of unfractionated bone marrow, we demonstrated that C-Kit(BR) cells c ontained low or undetectable levels of mRNA for c-fms, granulocyte col ony-stimulating factor receptor, interleukin 5 receptor (IL-5R), and I L-7R These same cells had moderate levels of mRNA for erythropoietin r eceptor, IL-3R subunits IL-3R alpha (SUT-1), AIC-2A, and AIC-2B, IL-6R and its partner gp-130, and the transcription factor GATA-1 and high levels of mRNA for transcription factors GATA-2 p45 NF-E2, and c-myb. We conclude from these Endings that PHSCs are programed to interact wi th stem cell factor, IL-3, and IL-6 but not with granulocyte or macrop hage colony-stimulating factor, These findings also indicate that GATA -2, p45 NE-E2, and c-myb activities may be involved in PNSC maintenanc e or proliferation.