实时荧光定量聚合酶链反应检测B7-H4基因表达的方法学构建

目的 建立实时荧光定量聚合酶链反应(PCR)检测协同刺激分子B7-H4基因表达的方法.方法 采用自行设计的检测协同刺激分子B7-H4及内参照基因GAPDH的引物及TaqMan探针,经优化反应体系及反应条件后,检测B7-H4及GAPDH的基因表达.将B7-H4和内参照基因GAPDH的PCR扩增产物经测序鉴定正确并纯化后分别与pMD19-T载体连接,克隆构建含B7-H4及GAPDH基因片段的重组质粒,作为实时荧光定量PCR检测B7-H4及GAPDH基因表达的标准品.将重组质粒标准品进行定量及梯度稀释,建立标准曲线.结果 PCR扩增产物分别经测序证实为B7-H4及GAPDH基因的特异性片段.该法检测B7-H4基因表达的灵敏度为527 copies/ml,线性范围为5.27×102～5.27×107 copies/ml,标准曲线方程为:Y=-3.1395X+41.805,直线回归相关系数r=0.995,批间变异系数范围为2.39%～3.59%,扩增效率108.2%.该法检测GAPDH基因表达的灵敏度为386 copies/ml,线性范围为3.86×102～3.86×107copies/ml,标准曲线方程为:Y=-3.2436X+41.083,直线回归相关系数r=0.999,批间变异系数范围为2.26%～3.86%,扩增效率103.4%.结论　成功构建实时荧光定量PCR检测协同刺激分子B7-H4基因表达的方法,该方法 特异性好、灵敏度高、重复性好.

Abstract：

Objective To establish a real-time polymerase chain reaction (PCR) method to detect costimulatory molecule B7-H4 gene expression. Methods The mRNA levels of costimulatory molecule B7-H4 and the reference gene GAPDH were detected by using real-time PCR using TaqMan technology. The primers and TaqMan probes of B7-H4 and GAPDH were designed. The B7-H4 and internal reference gene GAPDH fragments in pure form from classical PCR amplification were cloned into pMD19-T vector, and recombinant plasmids were used as the standard substances of B7-H4 and GAPDH quantitative detection.Standard curves were established using a serial dilution of quantified plasmids to measure B7-H4 and GAPDH. The reaction systems were optimized, and the sensitivity, specificity and reproducibility were evaluated. Results The amplification products were confirmed as the specific fragments of B7-H4 and GAPDH by DNA sequencing instrument. For B7-H4, the sensitivity was 527 copies/ml. The linear range was from 5.27 × 102 to 5.27 × 107 copies/ml, the standard curve equation was Y = - 3. 1395X +41. 805, the correlation coeffecient was 0. 995, the interassay coefficient of variations was 2. 39% -3.59%, and the amplification efficiency was 108.2%; For GAPDH, the sensitivity was 386 copies/ml. The linear range was from 3. 86 × 102 to 3.86 × 107 copies/ml, the standard curve equation was Y = - 3. 2436X +41. 083, the correlation coeffecient was 0. 999, the interassay coefficient of variations was 2. 26% -3. 86%, and the amplification efficiency was 103.4%. Conclusion The real-time PCR system for quantifying costimulatory molecule B7-H4 mRNA levels has been established successfully with high specificity, sensitivity and good repeatability.

Establishment of real-time PCR method on detecting costimulatory molecule B7-H4 expression

Objective To establish a real-time polymerase chain reaction (PCR) method to detect costimulatory molecule B7-H4 gene expression. Methods The mRNA levels of costimulatory molecule B7-H4 and the reference gene GAPDH were detected by using real-time PCR using TaqMan technology. The primers and TaqMan probes of B7-H4 and GAPDH were designed. The B7-H4 and internal reference gene GAPDH fragments in pure form from classical PCR amplification were cloned into pMD19-T vector, and recombinant plasmids were used as the standard substances of B7-H4 and GAPDH quantitative detection.Standard curves were established using a serial dilution of quantified plasmids to measure B7-H4 and GAPDH. The reaction systems were optimized, and the sensitivity, specificity and reproducibility were evaluated. Results The amplification products were confirmed as the specific fragments of B7-H4 and GAPDH by DNA sequencing instrument. For B7-H4, the sensitivity was 527 copies/ml. The linear range was from 5.27 × 102 to 5.27 × 107 copies/ml, the standard curve equation was Y = - 3. 1395X +41. 805, the correlation coeffecient was 0. 995, the interassay coefficient of variations was 2. 39% -3.59%, and the amplification efficiency was 108.2%; For GAPDH, the sensitivity was 386 copies/ml. The linear range was from 3. 86 × 102 to 3.86 × 107 copies/ml, the standard curve equation was Y = - 3. 2436X +41. 083, the correlation coeffecient was 0. 999, the interassay coefficient of variations was 2. 26% -3. 86%, and the amplification efficiency was 103.4%. Conclusion The real-time PCR system for quantifying costimulatory molecule B7-H4 mRNA levels has been established successfully with high specificity, sensitivity and good repeatability.