Analysis of expression of transcription factors during erythroid development of hematpoietic stem.

谱系特异性转录因子GATA-1和NF-E2在红细胞生成和巨核细胞生成中起重要作用。为了阐明人类造血干细胞的红系发育，我们克隆了新的NF-E2相关转录因子Nrf3、BACH1和BACH2。尽管正常的巨核细胞发育需要体内存在功能性的GATA-1因子，但GATA结合因子的其他成员在巨核细胞分化过程中的作用尚不清楚。在这篇报道中，我们检测了GATA-1和GATA-2，以及另一种GATA结合因子EVI-1在单代液体培养系统中培养前后的表达。在只含有血小板生成素的培养中，GATA-1和GATA-2的表达均增加，并维持在较高水平。相反，在单代红系培养中，GATA-2的表达下降，尽管GATA-1保持在较高水平。此外，EVI-1在巨核系和红系中的表达谱与GATA-2非常相似。由于与GATA结合位点相关的Ets结合位点存在于所有被描述为对巨核细胞特异性表达重要的区域，我们也分析了Ets-1的表达。有趣的是。Ets-1仅在巨核系细胞中被诱导。巨核细胞和红系细胞的分化途径密切相关，这两个谱系细胞共享许多谱系特异性转录因子。然而，结果表明，这些转录因子在巨核细胞中的表达谱与红系不同。在原代巨核细胞分化过程中GATA结合因子水平的动态变化表明，这些因子的水平可能影响向特定的造血途径的进展。

Lineage specific transcription factors, GATA-1 and NF-E2 are essential for erythropoiesis and megakaryocytopoiesis. In order to shed light on the erythroid development of human hematopoietic stem cells, we performed cDNA cloning of novel NF-E2 related transcription factors, Nrf3, BACH1 and BACH2.Although normal megakaryocytic development has been shown to require the presence of a functional GATA-1 factor in vivo, the role of other members of the GATA binding factors during megakaryocytic differentiation is unclear. In this report, the expression of GATA-1 and GATA-2, and another GATA binding factor EVI-1 has been examined in enriched cord blood progenitors before and after culture in a well-characterized unilineage liquid culture system. In the culture containing only thrombopoietin, which show exclusive megakaryocytic differentiation, both GATA-1 and GATA-2 expression was increased and maintained at high levels. In contrast, GATA-2 expression declined in unilineage erythroid culture, although GATA-1 remained at a high level. Furthermore, the profile of EVI-1 expression in megakaryocytic and erythroid lineages was very similar to that of GATA-2. Because Ets binding sites associated with GATA binding sites are present in all regions that have been described as important for megakarycyte-specific expression, we also analyzed Ets-1 expression. Interestingly. Ets-1 was induced only in megakaryocytic lineage cells. Megakaryocytic and erythroid differentiation pathways are closely related to each other, and these two lineage cells share a number of lineage-specific transcription factors. However, the results showed that the profile of the expression of these transcription factors in megakaryocytic cells is distinct from that of erythroid lineage. The dynamic changes in the levels of GATA binding factors that occur during primary megakaryocytic differentiation suggest that the levels of these factors may influence the progression to specific hematopoietic pathways.