Analysis of the expression profile of lineage-specific transcription factors in leukemia cells

GATA-2的表达与造血祖细胞的增殖分化能力有关，抑制GATA-2的表达可能是造血祖细胞分化所必需的。因此，阐明GATA-2基因表达的调控机制可能有助于深入了解造血细胞分化的早期阶段，并有助于阐明白血病发生的机制。在本研究中，我们分析了白血病细胞中GATA基因的表达谱，并分析了GATA-2基因的调控机制。(1)在已建立的白血病细胞系中，GATA-2的表达与CD34抗原的表达密切相关。为了确定GATA因子在恶性造血细胞中的表达谱是否被保留或改变，我们分析了白血病儿童的原代白血病原始细胞，发现肿瘤和相应的正常细胞之间存在GATA因子的相关性。也就是说，在大多数髓系…中较多的S白血病患者，白血病细胞表达GATA-2mRNA和CD34、c-kit抗原。而淋巴细胞白血病(ALL)患者CD34阳性细胞中未检测到GATA-2mRNA和c-kit抗原。GATA-3mRNA在所有T-ALL病例中均有表达，但在所有B-ALL中均不表达。因此，对GATA因子的表达分析可能为确定未分类白血病的谱系承诺提供有用的工具。(2)我们分离并鉴定了小鼠GATA-2基因，发现GATA-2的表达受两个不同的启动子调控。一种(IG启动子)通常用于表达GATA-2的组织和细胞系。另一个启动子(IS启动子)调控GATA-2基因在造血细胞中的表达。(3)利用转基因小鼠体内检测了小鼠GATA-2基因座的调控活性。反式基因的5‘端含有约7kbp的序列，是β-半乳糖苷酶报告基因在腹主动脉旁、腹主动脉-中肾区域和神经组织中特异表达的第一外显子，原位杂交分析表明报告基因的表达特异性地概括了GATA-2在这些组织中的内源性表达谱。较少

The expression of GATA-2 is related to proliferative versus differentiated capability of hematopoietic progenitor cells, and suppression of GATA-2 seems to be essential for hematopoietic differentiation. Therefore, elucidation of the mechanisms controlling GATA-2 expression may offer insight into the earliest aspects of hematopoietic cellular differentiation and may help clarify the mechanisms underlying leukemogenesis, In the present study, we analyzed GATA expression profiles in leukemia cells and also analyzed the regulatory mechanism of GATA-2 gene.(1) The expression of GATA-2 is closely linked with that of the CD34 antigen in established leukemia cell lines. To ascertain whether the expression profiles of GATA factors are preserved or changed in maligant counterparts of hematopoietic cells, we analyzed primary leukemic blasts from leukemic children, and found a correlation between tumor and respective normal cells in terms of the GATA factors. Namely, in the majority of myelogenou … More s leukemia cases, GATA-2 mRNA expression and the expression of CD34 and c-kit antigens on leukemic cells were demonstrated. In contrast, GATA-2 mRNA and c-kit antigen could not be detected in CD34-positive cells from lymphoblastic leukemia (ALL) patients. GATA-3 mRNA was exressed in all T-ALL cases, but not in any precursor B-ALL.Therefore, exprression analysis of GATA factors may provide a useful tool to determine the lineage commitment of unclassified leukemia.(2) We isolated and characterized the murine GATA-2 gene, and found that GATA-2 expression is regulated by two distinct promoters. One (IG promoter) is used in general in the tissues and cell lines that express GATA-2. The other promoter (IS promoter) regulates the expression of GATA-2 specifically in hematopoietic cells.(3) We examined the regulatory activity of the mouse GATA-2 genomic locus in vivo using transgenic mice. Trans genes containing about 7 kbp of sequence flanking the 5' end of the IS first exon direct expression of BETA-galactosidase reporter gene specifically to the para-aortic splanchnopleula, aorta-ganad-mesonephros region and in the neural tissues, In situ hybridization analysis showed that reporter gene expression specifically recapitulates the endogenaous expression profiles of GATA-2 in these tissues. Less