Phosphorylation of transcription factors is important in posttranslational control of protein function. The indispensable zinc-finger transcription factor, Gata1, is phosphorylated constitutively at 6 serine residues (26, 49, 72, 142, 178, 187), and at a seventh (310) following induction of erythroid differentiation. However, the biologic consequences of phosphorylation with respect to function...

Electrophoretically pure human interleukin-1 (IL-1) beta was found to stimulate human fibroblasts in a monolayer culture to elaborate colony-stimulating activity (CSA). Supernatant fluids from cultures induced with increasing concentrations of IL-1 were found to stimulate colony formation of myeloid (CFU-GM), erythroid (BFU-E), and multipotent (CFU-GEMM) progenitor cells in a dose-dependent fas...

Twelve cases of transient erythroblastopenia of childhood (TEC) have been studied to evaluate their marrow cell erythropoiesis in vitro and the effect on it of their serum or IgG. The number of colony-forming units-erythroid (CFU-E) and burst-forming units-erythroid (BFU-E) in the bone marrow of nine cases was extremely variable and did not allow any conclusion regarding the pathogenesis of thi...

Antibody L4F3 is a murine monoclonal antibody that recognizes an antigen expressed on in vitro colony-forming cells, including virtually all CFU-GM, CFU-Meg, BFU-E, and CFU-Mix. In the present study we examined whether cells that do not express the L4F3 antigen include precursors of hematopoietic colony-forming cells. Colony-forming cells were depleted from marrow by treatment with L4F3 and com...

The requirement of c-Myb during erythropoiesis spurred an interest in identifying c-Myb target genes that are important for erythroid development. Here, we determined that the neuropeptide neuromedin U (NmU) is a c-Myb target gene. Silencing NmU, c-myb, or NmU’s cognate receptor NMUR1 expression in human CD34 cells impaired burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid ...

Effects of interleukin-6 (IL-6) on cycling status and clonogenic maturation of human fetal (cord blood) and adult hematopoietic progenitors were compared. Adult marrow cells were incubated for various lengths of time with various concentrations of IL-6, in a serum-free system, after which tritiated thymidine suicide studies were performed. After incubation of 2 to 5 x 10(6) cells/mL for 4 hours...

Antibody 14F3 is a murine monoclonal antibody that recognizes an antigen expressed on in vitro colony-forming cells, including virtually all CFU-GM. CFU-Meg, BFU-E, and CFUMix. In the present study we examined whether cells that do not express the 14F3 antigen include precursors of hematopoietic colony-forming cells. Colony-forming cells were depleted from marrow by treatment with l4F3 and comp...

The effects of a single dose (150 mg/kg) of 5-fluorouracil on mature erythroid and erythropoietic and multipotential in vitro precursor populations in the bone marrow and spleen and circulating biologically (erythroid colony forming unit [CFU-E] assay) and immunologically active (enzyme-linked immunosorbent assay) erythropoietin (Epo) are described. All mature erythroid (reticulocytes, erythroc...

Erythroid colonies from cord blood in which both late (CFU-E) and early (BFU-E) erythroid precursors are present, were grown by the plasma clot technique. Hemoglobin (Hb) synthesis was studied and compared in fresh reticulocytes. 7-day-old colonies. and 14-day-old colonies. In the 8 cases studied, the proportion of HbA synthesis progresssively increased from circulating reticulocytes to 7-day-o...

We have demonstrated that the cyclohexanone method for the extraction of hematin can be used to measure hemoglobin synthesis induced by erythropoietin (epo) in mouse bone marrow cells cultured in medium containing methyl cellulose. The time course of hemoglobin synthesis by mouse marrow cells showed two effects due to epo: an increase in hemoglobin synthesis at day 2, which corresponded to the ...