我国彝族另一新的DR15(2)等位基因的核苷酸序列分析

Nucleotide sequence of another novel DR15(2) allele in Yi Nationality Chinese

目的对在用ＰＣＲ／ＳＳＯ方法作我国彝族群体样本ＨＬＡＤ区寡核苷酸分型中发现的１例ＤＲＢ１的杂合子进行等位基因序列分析。方法用ＤＲＢ基因类引物扩增该特殊的ＤＲＢ１杂合子细胞基因组的ＤＲＢ基因的第二外显子。扩增产物经纯化转染大肠杆菌ＪＭ１０１，克隆后再经酚／氯仿抽提后得到单链Ｍ１３ＤＮＡ。利用ＡＢＩ３７７测序仪自动测序。结果彝族这一特殊的ＤＲＢ１杂合子细胞的ＤＲＢ１基因阳性克隆，经序列分析证实了该ＤＲＢ１杂合子中一个等位基因确为ＤＲＢ１＊１２０２，与ＰＣＲ／ＳＳＯ分型一致；另一个新等位基因ＤＲＢ１＊１５Ｙ２（暂定）等位基因在第二外显子的４７位由编码苯丙氨酸的ＴＴＣ（ＤＲＢ１＊１５０２）变为编码酪氨酸的ＴＡＣ。结论在云南彝族样本中发现的ＤＲＢ１＊１５Ｙ２，其４７位由ＴＡＣ（酪氨酸）置换了相应于ＤＲＢ１＊１５０２的ＴＴＣ（苯丙氨酸）。在我国这样一个多民族国家中，就ＨＬＡ系统而言，可能还有更多新等位基因有待鉴定。

Objective One special DRB1 heterozygote which was found in oligotyping of HLA D region in Chinese Yi population by using PCR/SSO method, was to be sequenced for the gene of the allele. Methods Amplification of exon 2 of DRB gene in this heterozygote was carried out with genomic DNA templet and generic primers and the amplicon was cloned in M13 for further sequencing. Results One allele was identified as DRB1*1202, another allele whose PCR/SSO hybridization pattern was similar to but different from DRB1*1502 was considered as DRB1*15 variant. Analysis of nucleotide sequence revealed that this allelic variant differed from DRB1*1502 at codon 47 (TAC instead of TTC), resulting in the substitution of a tyrosine for phenylalanine in the DRβ chain. Conclusion The DRB1 heterozygote allele gene could be nominated as DRB1*15Y2 temporarily.