Analysis of expression of lineage-specific transcription factors during stem cell differentiation in aplastic anemia.

为了了解再生障碍性贫血的发病机制，我们研究了在正常造血逆转录酶介导的聚合酶链式反应(RT-PCR)中可能起重要作用的转录因子的表达。在本研究中，我们分析了GATA-1、GATA-2、NF-E2、Nrf1、Nrf2和Ets-1mRNA以及红系特异性基因如珠蛋白和促红细胞生成素受体(EPOR)在液体培养系统中诱导单系红系或巨核系分化的早期造血祖细胞的表达模式。结果表明，这些转录因子表达巨核细胞的特征相似，但不同于红系。这两个谱系之间的主要差异是GATA-2的表达模式。GATA-2的高水平表达随着巨核细胞成熟的进展而被诱导和维持，而该因子的表达随着红系终末分化的进展而下降。GATA-1、Nrf1和Nrf2在两个谱系中的表达谱非常相似。在我们的液体培养系统中，慢性粒细胞白血病(CML)原始细胞可以被诱导为两个谱系，证实了这些观察结果。核因子-E2是由一个谱系特异性亚基p45和一个普遍存在的亚基p18组成的异源二聚体，属于小MAF家族。我们首次克隆了人MafK和MafG的cDNA。令人惊讶的是，在红系和巨核细胞分化过程中，mafK和mafG mRNA以及P45NF-E2显着增加。此外，红系特异性基因，如珠蛋白和EPOR，在向两个谱系分化的过程中上调，表明两条分化途径非常接近。在本研究中，我们阐明了谱系特异性转录因子的正常表达模式，这些结果将对理解再生障碍性贫血的病理非常有用。

In order to understand the pathology of aplastic anemia, we have studied the expression of the transcription factors which may play important roles in normal hematopoiesis reverse transcriptase mediated polymerase chain reaction (RT-PCR). In this study, we analyzed the expression patterns of GATA-1, GATA-2, NF-E2, Nrf1, Nrf2 and Ets-1 mRNA as well as erythroid specific genes such as globins and erythropoietin receptor (EpoR) in purified early hematopoietic progenitor cells (HPCs) induced to unilineage erythroid or megakaryocytic differentiation in a liquid culture system. The results showed that the profile of these transcription factors expression megakaryocytic cells is similar but distinct from erythroid lineage. The major differences betweenthe two lineages were the expression pattern of GATA-2. The high level of GATA-2 expression is induced and maintained as megakaryocytic maturation progresses, whereas expression of this factor decline as erythroid terminal differentiation progresses. GATA-1, Nrf1 and Nrf2 showed very similar expression profile in both lineages. These observations were confirmed by using chronic myelogenous leukemia (CML) blasts which can be induced into both lineages in our liquid culture system. NF-E2 is a heterodimer composed of a lineage-specific subunit p45 and a ubiquitous subunit p18 which belongs to small Maf family. We cloned the human cDNAs for MafK and MafG for the first time. Surprisingly mafK and mafG mRNA increased markedly during erythroid and megakaryocytic differentiation as well as p45 NF-E2. Moreover, erythroid-specific genes such as globins and EpoR were upregulated during the differentiation toward the both lineages indicating the both differentiation pathways are very closed. In present study, we clarify the normal expression pattern of lineage-specific transcription factors and these results will be very useful of understanding the pathology of aplastic anemia.