Developmental changes in the expression of transcription factors GATA-1, -2 and -3 during the onset of human medullary haematopoiesis.

Regulation of gene expression during the ontogeny of haematopoiesis in the human fetal bone marrow is poorly understood. Studies in mice demonstrated that GATA-1, -2 and -3 play pivotal roles in haematopoiesis. In this study, we identified GATA-1-, GATA-2- and GATA-3-expressing cells in bone marrow sections and analysed the expression of GATA-transcription factors during the development of human fetal bone marrow haematopoiesis using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). We showed that GATA-1, -2 and -3 were expressed only in haematopoietic cells in the bone marrow. RT-PCR analysis demonstrated that (1) GATA-1 expression significantly increased during gestation; (2) GATA-2 expression peaked at the onset of medullary haematopoiesis, declined thereafter, and remained at a constant level after 30 weeks post conception; and (3) GATA-3 expression revealed no changes during development. The results indicated that the onset of medullary haematopoiesis in humans is accompanied by high expression of GATA-2, reflecting high proliferation rates of early haematopoietic progenitor cells, whereas expression of GATA-1 mirrors haematopoietic activity.