HbF and HbA production in erythroid cultures from human fetuses and neonates.
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Cells, Cultured↗
Biomedical subjects
B Nakamoto
Publications and source records attributed to B Nakamoto.
Erythroid progenitors circulating in the blood of adult individuals produce fetal hemoglobin in culture.
Erythroid colonies, raised from erythroid stem cells circulating in the peripheral blood of normal adult individuals, synthesize considerable amounts of fetal hemoglobin. In cultures from persons with sickling disorders, amounts of hemoglobin F that are known to inhibit sickling in vivo are produced. The results provide evidence that primitive erythroid progenitors are able to express the hemoglobin F production program and that cultures of mononuclear cells of the adult blood can be used to investigate the mechanisms involved in regulation of gamma-globin gene switching.
Adult↗
A haemoglobin switching activity modulates hereditary persistence of fetal haemoglobin.
During human development there is a switch from fetal to adult haemoglobin formation, reflecting the differential expression of fetal (G gamma and A gamma) and adult (beta and delta) globin genes. Mutations that inhibit this switch produce variants of the syndrome of hereditary persistence of fetal haemoglobin (HPFH). Adult heterozygotes for these mutants produce 15-30% fetal haemoglobin (HbF) in their red cells. The general assumption is that the mutations result in a permanent switching on of gamma-globin genes. Here, however, we show that fetal globin expression can be turned off in cultures of HPFH cells by an uncharacterized factor in fetal sheep serum. This is the first demonstration that mutations affecting the developmental expression of globin genes can be modulated by exogenous factors. The findings raise the possibility that the phenotype of HPFH is not simply the direct result of mutations in or around globin genes but the consequence of the mutations on the interaction of globin genes with trans-acting regulatory factors.
Adult↗