myc拮抗基因Mad1、Mxi1和Rox在白血病细胞中的表达和突变

Expression and mutation of myc antagonist genes Madl, Mxil and Rox in leukemia cells

目的分析 Mad1、Mxi1和 Rox 基因突变在白血病发病中的作用。方法利用逆转录-聚合酶链反应(RT-PCR)、单链构象多态性(SSCP)分析及 DNA 序列分析技术检测了26例初治急性白血病(AL)患者、30名健康对照者和7种白血病细胞株中 Mad1、Mxi1和 Rox 基因表达及突变情况。结果 RT-PCR 检测结果显示所有标本中均可检测到 Mad1、Mxi1和 Rox 基因的表达;SSCP 分析结果显示所有标本中有4个位点发生多态性改变:Mad1中12个位点,Mxi1和 Rox 中各1个位点。DNA 序列分析显示所有标本中有9个位点发生错义突变:Mad1中2个位点均发现于初治 AL 患者;Mxi1中4个位点,其中3个位点发现于初治 AL 患者,1个位点发现于 KG1细胞株;Rox 中3个位点均发现于初治AL 患者。26例初治 AL 患者 Mad1、Mxi1和 Rox 基因的突变发生分别为2例、3例和3例。结论首次在 AL 患者细胞中发现 Mad1、Mxi1和 Rox 基因突变,提示 Mad1、Mxi1和 Rox 基因的突变可能与白血病的发病有关。

Objective To investigate the expression and mutation of Madl, Mxil and Rox genes in leukemia cells. Methods Expression and mutation of Madl, Mxil and Rox genes in bone marrow mononu- clear cells （BMMNC） from 26 de novo acute leukemia （AL） patients, and in peripheral blood mononuclear cells （PBMNC） from 30 healthy volunteers, as well as in 7 human leukemic cell lines were analyzed by re- verse transcription-polymerase chain reaction （ RT-PCR）, single strand conformational polymorphism （SSCP） and DNA sequencing. Results RT-PCR showed that all the above cells expressed Madl, Mxil and Rox mRNA. SSCP revealed four polymorphisms： two in Madl, one each in Mxil and Rox. DNA sequencing de- tected nine missense mutations： two in Madl in AL patients, four in Mxil （three in AL patients and one in KG-1 cell line）, and three in Rox in AL patients. The mutations of Madl, Mxil and Rox mRNA were detec- ted in 2, 3 and 3 patients, respectively. Conclusion It is for the first time to demonstrate the mutations of Madl, Mxil and Rox genes in AL patients suggesting these mutated genes involve in the pathogenesis of leu- kemia.