中国人群中肾上腺素α2A受体基因SNP的分布及其对基因表达的影响

目的：在中国人群肾上腺素α2A受体(α2A-AR)基因中搜寻单核苷酸多态性(SNP)并研究其对基因表达的影响。方法：对α2A-AR基因进行序列分析，搜寻SNP。从全血中提取基因组DNA，扩增包含G／C多态性位点的239bpDNA片段。利用PCR-RFLP方法对中国北方人群α2A-AR基因-1296bp位点SNP进行基因分型。利用凝胶阻滞方法研究含G／C的390bp DNA片段与细胞核提取物的结合。结果：在中国北方人群α2A-AR基因中共发现2处SNP。-1296位SNP等位基因G、C频率分别为0．61和0．39，基因型GC,，C,C，CC频率分别为0．34，0．54，0．13。EMSA结果表明，细胞核提取物与-1296bp为C的DNA片段可特异性结合。结论：中国北方人群啦α2A-AR基因中存在2处SNP，调控区(-1296位)SNP等位基因为C的DNA片段可与特异性蛋白质结合，可能通过这一机制影响基因表达。

SNP Identification in α2A-Adrenergic Receptor Gene in Chinese and the Effect on Gene Expression

Objective: To scan single nucleotide polymorphism ( SNP ) in Chinese alpha-2A adrenergic receptor( α2A-AR )gene and study the effcts of the SNP on the gene expression .Methods: The complete sequence of α2A-AR gene was analyzed with autonated DNA sequencer to scan SNPs. Genomic DNA was extracted from whole blood and a 239 bp fragmnent containing the G/C polymorphism was amplified with PCR using a pair of specific primers.PCR-RFLP was used to perform the genotyping of the SNP at the site- 1 296 bp of the people in the North of China. Electrophoresis mobility shift assay( EMSA )was used to study the binding of the 390bp fragments(- 1 414-1 025 bp) with G or C at the site-1 296 bp and nuclear extracts. Results: In our study, two SNPs werefound in α2A-AR gene. Allele frequeneies of the SNP at the site- 1 296 bp were 0.61 and 0.39 for G and C, and the genotype frequencies were 0.34,0.54 and 0.13 for GG, GC and CC respectively from the people in the North of China.In the EMSA, a specific binding appeared in the complex of nuclear extracts and DNA with C at- 1 296 bp. Conclusion: Two SNPs exist in a2A-AR gene from the people in the North of China, and DNA fragment with allele C of the SNP at the site- 1 296 bp could bind with a specific protein, which could influence the gene expression.