cDNA微阵列制作的优化

为了优化筛检cDNA微阵列中靶基因的最适长度、浓度及点样溶液的种类，设计持家基因beta actin和GAPDH RT-PCR 3对引物，产物长度在189～1 078 bp之间，以乙肝病毒DNA片段为阴性对照，扩增纯化后分别溶于3×SSC、50%DMSO及0.5mol/L碳酸盐缓冲液（pH=9.0）中，调整浓度分别为0.5μg/μL、1.0μg/μL和1.5μg/μL，比较上述不同条件的杂交结果。结果表明，杂交具有较好的特异性，阴性对照（乙肝病毒）和空白对照（点样溶液）均未见杂交信号；3种长度的同一靶基因杂交信号强度无明显差别（beta actin P=0.378；GAPDH P=0.866）；3种点样溶液中以50%DMSO杂交信号最好，较强且均匀一致(P=0.0001)，其余2种差异不显著(P=0.142)；3种浓度靶基因杂交信号差异不显著(P=0.648)，浓度高者信号略强。短片段靶基因（200 bp左右）可获得与长片段靶基因（1 000 bp以上）一样较好的杂交信号，点样溶液以50%DMSO效果最好，靶基因浓度为0.5μg/μL时即可得到较好的杂交结果。 Abstract:To optimize and screen the most suitable target gene length,concentration and printing solution in cDNA microarray,housekeeping genes,such as beta actin and GAPDH,were selected as targets and hepatitis B virus gene as negative control.The RT-PCR primers that spanned at least one intron and whose products were at between 189 bp and 1 078 bp were designed with primer premier 5.0,so did the hepatitis B virus gene PCR primer.After polymerase chain reaction,the products were purified with ethanol and dissolved in 3×SSC,50% DMSO and 0.5mol/L carbonate buffer（pH=9.0）respectively.The concentrations of target genes were adjusted at 0.5μg/μL,1.0μg/μL and 1.5μg/μL.The hybridization signals had a good specificity.No signal showed in either negative control (HBV) or blank control (printing solution only).There was no significant difference in target gene lengths.The P value of beta actin (189 bp,491 bp,974 bp) and GAPDH (227 bp,552 bp,1 078 bp) was 0.378 and 0.866 respectively.There was no significant difference among concentrations（P=0.648）,too.However,the higher the concentration was,the stronger the signals would be.Among the three kinds of printing solution,50% DMSO was the best（P=0.0001）,while the other two had no difference by multi-comparison(P=0.142).The target gene at length between 200 bp and 1 000 bp has got the same hybridization signals.50%DMSO printing solution and the target gene concentration of 0.5μg/μl are suitable for good hybridization.

Optimization of cDNA Microarray Fabrication