Molecular Analysis of Maturation Arrest Mechanism of Myeloid Leukemogenesis

我们一直致力于利用髓系标记基因、细胞周期相关基因和转录因子基因对髓系白血病发生的成熟阻滞机制进行分子分析。首先，我们从CML患者的G-CSF刺激白血病细胞中克隆了一个新的髓细胞标记基因g -1 （G-CSF诱导基因-1）。结果表明，gg -1基因在髓系细胞中以mRNA和蛋白水平表达。这种新基因在成熟细胞中以蛋白质水平表达得更多。电镜结果显示该蛋白的微粒体定位。该基因与碱性磷酸酶、髓过氧化物酶、防御素等髓细胞特异性标记基因的表达对分析成熟阻滞的分子机制具有重要意义。其次，我们试图分析导致骨髓细胞谱系成熟阻滞的第一个事件。我们特别关注PEBP2 α和PEBP2 β基因，它们分别是DNA结合和DNA非结合转录调节基因，形成异源二聚体，它们都被认为与白血病发生密切相关。PEBP2 β基因敲除小鼠的胚胎显示了严重的造血功能，包括骨髓细胞成熟阻滞。由于PEBP2 a基因缺陷也被报道强烈参与敲除小鼠的造血抑制，这两个分子被认为是在髓性白血病中发现的成熟阻滞的负责分子之一。使用正常的对应基因可能对PEBP2 α或PEBP2 β基因破坏的某些类型的髓性白血病有用。我们还研究了其他转录因子的作用，包括Evi-1和细胞周期特异性分子，以阐明这些分子在髓性白血病细胞成熟阻滞中的作用。

We have been focusing on the molecular analysis of maturation arrest mechanism underlying the myeloid leukemogenesis using myeloid marker genes, cell cycle related genes and trancriptional factor genes. First of all, we have cloned a novel myeloid cell marker gene of GIG-1 (G-CSF inducible gene-1) from G-CSF stimulated leukemia cells from CML patients. The results demonstrated that GIG-1gene was expressed in myeloid lineage cells at the levels of mRNA and protein. This novel gene was paricularly expressed more in matured cells at protein levels. The elecromicroscopic results revealed the microsomal localization of this protein. The expression of this novel gene together with other myeloid specific marker genes of alkaline phosphatase, myeloperoxidase, defensin are very important to analyze the molecular mechanisms of maturation arrest. Second, we tried to analyze the first event which induced the maturation arrest of myeloid cell lineage. Particulary we focused on PEBP2 alpha and PEBP2 beta genes, DNA binding and DNA nonbinding transcriptional regulating genes respectively, forming heterodimers and both of them are considered strongly involoved in leukemogenesis. The embryos of knockout mice of the PEBP2 beta revealed the severe pictures of hematopoiesis including maturation arrest of the myeloid cells. As the defect of PEBP2 a gene was also reported to be strongly involved in the suppressed hematopoiesis in knockout mice, both of these molecules are consiered to be one of the responsible molecule of maturation arrest found in myeloid leukemia. The use of the normal counterpart genes might be useful for some types of myeloid leukemia with the genetic disruptios of PEBP2 alpha or PEBP2 beta. We also studied the roles of othere transcriptional factors including Evi-1 and cell cycle specific molecules for elucidating the roles of these molecules in the maturation arrest of myeloid leukemia cells.