急性白血病多药耐药相关消减cDNA文库的构建与鉴定

研究目的是构建急性白血病多药耐药相关消减cDNA文库，以用于白血病多药耐药(MDR)相关基因的筛选。采用改良的消减杂交方法建立急性白血病耐药细胞差异表达基因cDNA文库，提取HL-60／VCR与HL-60细胞mRNA，将HL-60／VCR细胞mRNA用Cap-Finder法反转录成cDNA，与以常规反转录的HL-60细胞cDNA为模板．PCR合成生物素标记的扣除探针进行杂交。杂交产物用Sephacryl S-400柱和具有链亲和素作用的磁殊纯化后，得到差异表达cDNA。PCR法特异扩增，进行T-A克隆建成消减cDNA文库，并通过反向点杂交鉴定其质量。结果表明：构建急性白血病多药耐药相关消减cDNA文库所需样本量少且时间短，全长或近全长的cDNA分子较多(约达总数的2／3)，质量较高。结论：成功构建急性白血病多药耐药相关消减cDNA文库，为筛选白血病耐药相关基因奠定了基础。

Construction and Analysis of Subtractive cDNA Library Associated with Multidrug Resistance of Acute Leukemia

The study was aimed to construct subtractive cDNA library associated with multidrug resistance (MDR) of acute leukemia for screening genes related to MDR in leukemia. The improved PCR-based subtractive hybridization was performed to clone differential genes between HL-60/VCR and HL-60 cell line. The mRNA of HL-60/VCR and HL-60 cell line were isolated. Then the mRNA of HL-60/VCR group was reversely transcribed into cDNA by Cap-Finder method,and the mRNA of HL-60 was reversely transcribed into cDNA by ordinary method to be marked by biotin for the hybridization next with HL-60/VCR cDNA. After hybridizing,filtrating through the sephacryl S-400 column,absorbing by the magnetic beads,and amplifying by PCR method,the fragments were cloned by T-A method and the cDNA library was constructed. Then the quality of cDNA library was identified by dot-blotting hybridization method. The results showed that after constriction,the library demonstrated its good quality. There was a high proportion of large fragments in this library. From small amount of samples a large amount of candidate fragments could be screened rapidly at once by dot-blotting hybridization. It is concluded that a differentially-expressed subtractive cDNA library in MDR of leukemia with high quality and larger fragments can be efficiently constructed by improving subtractive hybridization and selective PCR method.