ANALYSIS OF TRANSCRIPTIONAL REGUlATION IN ADULT T-CELL LEUKEMIA

我以前报道过成人t细胞白血病细胞系中两种转录因子ISCAT和GATA-4的异常表达。在本研究中，作为下一步，我将通过两种方法来检验这两种因子与白血病发生的关系：(1)检测ATL细胞中mRNA表达因子。(1)对22例临床样本（2例成人t细胞白血病、4例恶性淋巴瘤白血病转化、6例慢性骨髓性白血病、9例多发性骨髓瘤和1例毛细胞白血病）的总RNA进行纯化，并进行RT-PCR。每个样品中均未观察到扩增。由于这些因子在ATL细胞中与白细胞介素5的启动子结合，因此在没有这些因子在白血病发生中的意义的细胞中可能检测不到该信息。病毒感染是另一个可能的候选者，这些转录因子可能与发病机制有关，因为ISCAT在ebv感染的细胞系和ATL细胞系中都有表达。(2)从人胎盘基因组文库中分离到这些基因的5′调控区。将2kb片段连接到萤火虫荧光素酶报告基因上。将这些质粒与HTLV-1的反激活剂TAX共转染Jurkat细胞后，观察到适度的反激活。对启动子中负责的元素或区域的进一步鉴定有待进行。

I reported previously abnormal expression of two transcription factors, ISCAT and GATA-4, in adult T-cell leukemia cell lines. In this study, as the next step, I examined the relationship of these two factors and leukemogenesis in two approaches : (1) detection of mRNA expression factors in ATL cells.(1) Total RNA from twenty-two clinical samples (two adult T-cell leukemia, four leukemic transformation of malignant lymphoma, six chronic myelogenous leukemia, nine multiple myeloma and one hairy cell leukemia) were purified and RT-PCR was performed. No amplification was observed in each samples. Because those factors were identified to bind the promoter of interleukin 5 in ATL cells, the message might not be detected in cells which do not significance of these factors in leukemogenesis. Viral infection is another possible candidate in which those transcription factors may be relevant to pathogenesis, because ISCAT was expressed in EBV-infected cell lines as well as ATL cell lines.(2) The 5' regulatory region of those genes were isolated from human placenta genomic library. The 2kb fragments were ligated to firefly luciferase reporter gene. After cotransfection of these plasmids with TAX, the transactivator of HTLV-1, into Jurkat cells, moderate transactivation was observed. Further identification of responsible elements or regions in the promoters is to be performed.