CⅡTA基因编码区不同单倍型cDNA的功能研究

Functional study of the different haplotypes cDNA in the coding region of C Ⅱ TA gene

目的研究MHCⅡ类反式激活因子（CⅡTA）基因编码区非同义单核苷酸多态性（SNP）位点C19170G（Leu45Val）和C30799G（Ala500Gly）构成的4种不同单倍型eDNA的功能。方法将4种不同单倍型的真核表达载体和空载体分别转染至HeLa细胞。用RT—PCR和间接细胞免疫荧光技术检测未经转染的HeLa细胞、转染4种真核表达载体及空载体的HeLa细胞C1ITAmRNA与3种HLAⅡ类分子（HLA-DR、DP、DQ）的表达，并用流式细胞技术对其表达的3种HLAⅡ类蛋白进行定量分析。结果未经转染和转染空载体的HeLa细胞均无CⅡTA mRNA和3种HLAⅡ类分子的表达，而转染4种不同单倍型真核表达载体的HeLa细胞均出现CⅡTA mRNA表达，并表达3种HLAⅡ类分子。证实了转染4种不同单倍型真核表达载体后的HeLa细胞3种HLAU类分子表达水平差异无统计学意义（P均〉0．05）。结论中国人CⅡTA基因编码区这两个SNP位点的多态性（2个位点氨基酸的改变）不影响CⅡTA反式激活HLAⅡ类基因表达的能力。

Objective To study the function of 4 different haplotypes eDNA which are constructed by two non-homonymy single nueleotide polymorphism （SNP） sites C19170G （Leu45Val） and C30799G （Ala500Gly） in the coding region of human C Ⅱ TA gene. Methods HeLa cells were transfected with eukaryotic expression vectors containing four different haplotypes eDNA. C Ⅱ TA mRNA and HLA class Ⅱ antigen （HLA-DR, DP, DQ） were respectively detected by RT-PCR and indirect cell immunofluoreseence technique in the untransfected and transfected with four eukaryotic expression vectors and empty vectors HeLa cells. The quantity of HLA class Ⅱ antigen were analyzed by flow cytometry. Results No expression of C Ⅱ TA mRNA and HLA class Ⅱ antigen were observed on original HeLa cells and empty vector transfected cells. C Ⅱ TA mRNA expression was emerged, and the expression of HLA class Ⅱ antigen were observed in the HeLa cells transfeeted with eukaryotic expression vectors containing four different haplotypes eDNA. And there were not significantly different with the levels of HLA class Ⅱ antigen expression among HeLa cells transfected with eukaryotic expression vectors containing four different haplotypes eDNA （ P 〉 0.05 ）. Conclusion The SNP of Chinese at the sites C19170G（Leu45Val） and C30799G（AlaS00Gly） in the coding site of C Ⅱ TA gene did not influence capability of CⅡTA trans-activating HLA class Ⅱ gene expression.