三个群体MICA基因外显子2、3和4的多态性研究

目的 调查上海地区汉族、云南傣族和新疆维吾尔族3个群体MICA基因外显子2、3和4的多态性。方法 采用聚合酶链反应－序列特异的寡核苷酸探针杂交（polymerase chain reaction and sequence-specific oligonucleotide robing,PCR-SSOP）方法，分析183名汉族、41名傣族和66名维吾尔族正常人群的MICA胞外区等位基因多态性。结果 分别在汉族、傣族和维吾尔族中检测出10、7和9个MICA等位，其中MICA^*008在汉族和维吾尔族中频率最高，而傣族中MICA^*010的频率最高。3个民族MICA等位基因分布方式各不相同，而且维吾尔族的等位基因分布与另外两个民族相比，差异具有显著性。结论 MICA等位基因分布方式具有民族地区特异性。     

湖南汉族人群MICA基因多态性分析

为了解湖南地区汉族人群MICA基因第2、3和4外显子多态性分布特点,采用PCR-SSP方法对162名无亲缘关系湖南汉族人群MICA等位基因进行分析。结果显示:在湖南汉族人群中共检测出12个等位基因和28种基因型,各等位基因分布频率有差异,其中以MICA*00801基因频率最高(37.9%),其次为MICA*00201/020(20.1%)和MICA*010(17.3%),频率最低的是MICA*019和MICA*031。将MICA基因在湖南汉族人群中的分布与该基因在其他人群中的分布进行比较,显示MICA基因的分布在不同人群之间存在差异,可作为中国人群的遗传标志。     

湖北汉族人群甘露糖结合凝集素基因外显子1多态性与SLE关联性的研究

目的：分析湖北汉族人群甘露糖结合凝集素(Mannose-Binding LectionL或Mannose-Binding Protein,MBL或MBP)基因外显子1多态性，探讨其与系统性红斑狼疮(Systemic Lupus Erythematosus,SLE)的易感性关系。方法：采用异源双链杂交技术对111例健康正常人和41例SLE患者的MBL基因外显子1多态性进行分析。结果：①共检测出两种等位基因：野生型A和变异型B(在54位密码子由GGC→GAC)，未检出变异型C、D等位基因。②正常对照中A等位基因及B等位基因的基因频率分别为0．910和0．090，符合Hardy-Wernberg定律；与此前在日本人中报道的A及B等位基因频率0．767和0．233相比，变异型B的等位基因频率明显低于后者(P＜0．05)。③SLE病人组中B等位基因频率为0．146，高于正常对照组，但差异无显著性意义。结论：在湖北汉族人群中MBL基因外显子1具有遗传多态性，而且与已知其他人群的分布频率有一定差异。MBL基因外显子1的遗传多态性并不与系统性红斑狼疮相关联。     

强直性脊柱炎患者MICA基因第2、3和4外显子的多态性及其与HLA-B抗原的连锁不平衡

目的探讨皖籍汉族人群MICA基因（major histocompatibility complex class Ⅰchain-related gene A，MICA）第2、3、4外显子的多态性，及其与HLA-B抗原的连锁不平衡在强直性脊柱炎（ankylosing spondylitis，AS）发病中的作用。方法采用聚合酶链反应-序列特异性寡核苷酸探针杂交（polymerase chain reactionsequence-specific oligonucleotide probing，PCR-SS0）技术对56例AS患者和112名正常对照人群进行MICA基因第2、3、4外显子的多态性和HLA-B抗原的检测。结果AS患者和正常对照人群的MICA等位基因分布均以MICA＊008占优势，频率分别为32．14％和30．36％。两组人群MICA＊007等位基因的分布差异有统计学意义（X^2=10．18，P〈0．05，RR=2．50）。单倍型分析显示，AS患者和正常对照人群的MICA等位基因均显示出与多个HLA-B位点的连锁不平衡现象，两组间差异有统计学意义的单倍型为MICA＊007-B27（X^2=18．46，P〈0．05，RR=7．47）。分层分析结果显示，HLA-B27阳性与AS的相关性有统计学意义（P〈0．05），但MICA＊007基因与AS的相关性无统计学意义（P〉0．05）。结论AS患者中MICA＊007等位基因频率的显著升高可能源于MICA基因与HLA-B位点间的广泛连锁不平衡。     

贵州汉族TGF-β1基因多态性与系统性红斑狼疮相关性的研究

目的：探讨转化生长因子-β1（TGF-β1）基因启动子-509C/T多态性与贵州汉族人群系统性红斑狼疮（SLE）的相关性。方法：采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）技术，分析80例SLE患者及95例正常对照组的TGF-β1基因启动子-509C/T多态性。结果：SLE组与正常对照组-507C/T基因型频率分布有差异（P〈0.05），-509CC基因型SLE组高于对照组（35% vs 21.1%），而-509TT型SLE组明显低于正常对照组（18.75% vs 36.8%）；SLE患者组-509位点的等位基因频率与正常对照组比较差异也有显著性（P〈0.005），SLE组C等位基因频率显著高于对照组（58.1% vs 42.1%），T等位基因频率低于对照组（41.9% vs 57.9%）。结论：贵州汉族人群TGF-β1基因启动子-509C/T多态性与SLE显著相关。     

中国南方汉族人群MICA-STR的遗传多态性

目的人类MICA(MHC classⅠ chain relaed geneA)基因位于HIAⅠ类区HLA-B近着丝粒端46kb。MICA遗传多态性与器官移植、多种疾病的遗传易感性有密切关系。本工作研究中国南方汉族正常人群MICA基因第5外显子微卫星(MICA-STR)遗传多态性。方法采用荧光PCR/sizesequencing和PCR／SSP技术分析231例中国南方汉族健康个体MICA-STR等位基因及MICA缺失型(MICA*Del)频率。结果在该群体中发现MICA*A4、MICA*A5、MICA*A5．1、MICA*A6、MICA*A9、MICA*Del，其中以MICA*A5、MICA*A5．1最为常见，频率分别为0．362、0．313；共检出MICA*Del携带者3例，MICA*Del基因频率为0．006，该3例样本经PGWKSP定型，均为HLA-B48阳性。MICA-STR基因型分布符合Hardy-Weinberg平衡。结论中国南方汉族人群MICA-STR等位基因的构成不同于其他人群；此外，该人群存在低频率的MICA基因缺失。     

中国南方系统性红斑狼疮患者Fas-670基因多态性研究

目的:研究Fas-670基因多态性在中国南方地区汉族人群中的分布及其与系统性红斑狼疮(SLE)的相关性。方法:应用聚合酶链反应(PCR)-限制性片段长度多态性(RFLP)方法,对103例SLE患者和110例中国南方地区汉族正常对照者进行了Fas-670基因多态性检测。结果:SLE患者Fas基因-670位点基因型和等位基因频率与正常对照组比较无显著差异;而Fas基因-670位点基因型和等位基因频率分布,按性别分层后,男性和女性SLE患者分别与正常对照者比较以及SLE并发狼疮性肾炎(LN)患者和正常对照组比较及SLE并发LN患者与未并发LN患者间比较,均无显著差异。结论:Fas-670基因多态性与中国南方地区汉族系统性红斑狼疮无相关性。     

广东汉族人群MICA和MICB微卫星多态性分布

目的　调查广东地区汉族人群 MICA基因第 5外显子和 MICB基因第 1内含子微卫星多态性分布。方法　应用聚合酶链反应和荧光 ( 6 - FAM)自动化检测技术 ,对广东地区共 10 6名无亲缘关系样本进行 MICA和 MICB微卫星基因分型 ,并计算这两个微卫星的基因频率、基因型频率、个体鉴别力、期望杂合性、多态性信息含量和非父排除率。结果　MICA和 MICB微卫星基因型分布符合 Hardy- Weinberg平衡。MICA A5基因频率最高为 0 .2 877,A4基因频率则最低为 0 .132 1;A5 - 5 .1( 14 .15 % )和 A5 - 5 ( 10 .38% )基因型分布频率较高。 MICB CA14等位基因频率最高为 0 .32 5 5 ,CA19、CA2 8等位基因频率最低为0 .0 0 4 7,未检出 CA2 7。 CA14 - CA14 ( 14 .15 % )基因型分布频率较高。结论　 MICA基因第 5外显子和MICB基因第 1内含子微卫星适合作为中国人群的遗传标志 ,用于人类学、遗传疾病基因连锁分析、法医学亲子鉴定和个体识别等研究领域     

TLR5rs5744168基因多态性与广西壮、汉族人系统性红斑狼疮的相关性研究

目的:探讨TLR5rs5744168基因单核苷酸多态性与广西壮、汉族系统性红斑狼疮易感性的相关性以及种族间差异,初步阐明其在壮、汉族SLE发生发展中的作用.方法:采用聚合酶链反应PCR技术和直接测序的方法对33例壮族、44例汉族系统性红斑狼疮患者和72名壮、汉族健康对照者的TLR5rs5744168C/T基因多态性进行分析,比较组间基因型和等位基因频率的差异,并与主要临床指标进行相关性分析.结果:(1)广西地区壮、汉族SLE的TLR5 rs5744168的TT基因型均缺失;CC基因型频率在各组中均在90.0％～100.0％之间.(2)广西壮族SLE患者TLR5基因rs5744168 CC、CT基因型频率分别是0.939、0.061,汉族SLE患者相应基因型频率分别是0.977、0.023,与相应民族正常对照组间以及壮、汉族SLE间差异均无统计学意义(分别x2 =2.001 x2=2.235和x2 =0.723;均P＞0.05);壮族SLE患者的TLR5rs5744168 C、T等位基因频率分别是0.970、0.030,汉族SLE相应的C、T等位基因频率分别是0.989、0.011,与相应民族正常对照组间以及壮、汉族SLE间差异均无统计学意义(分别x2=1.970、x2 =2.166和x2=0.708;均P＞0.05).(3)TLR5rs5744168 CC、CT基因型及C、T等位基因与广西壮汉族SLE患者ds-DNA、ANA、肾损害临床表现和实验室检查均无相关性(均P＞0.05).结论:TLR5rs5744168基因多态性与广西壮、汉族SLE的易感性以及ds-DNA、ANA、肾损害临床实验室主要指标均无明显相关性,壮、汉族间亦不存在明显民族差异性.     

系统性红斑狼疮患者血清中Tim-1蛋白水平及其基因多态性

目的:检测T细胞免疫球蛋白黏蛋白域蛋白-1(Tim-1)在系统性红斑狼疮患者和健康对照组血清中的浓度,比较不同基因型间Tim-1蛋白的浓度,及其基因第4外显子插入/缺失多态性,分析其与系统性红斑狼疮的关系。方法:采用ELISA方法测定Tim-1蛋白在血清中的浓度;PCR反应检测TIM-1的第4外显子插入与缺失多态性,计算基因型与等位基因的频率。结果:系统性红斑狼疮患者和健康对照组血清中Tim-1蛋白的浓度分别是:(263.083±276.953)和(58.527±92.424)pg/ml,两组之间的差异有统计学意义;SLE患者TIM-1的第4外显子缺失/缺失纯合子与缺失/插入杂合子的Tim-1蛋白的浓度分别为(307.360±284.079)和(191.750±256.708)pg/ml,两组之间无显著性差异。健康对照组TIM-1的第4外显子缺失/缺失纯合子与缺失/插入杂合子的Tim-1蛋白的浓度分别为(70.295±109.917)和(40.468±41.739)pg/ml,两组之间无显著性差异。对照组的TIM-1的第4外显子缺失/缺失纯合子,缺失/插入杂合子,插入/插入纯合子基因型频率分别是0.617,0.321,0.062;系统性红斑狼疮患者相应的基因型频率是0.652,0.326,0.022。两组之间无显著性差异。结论:Tim-1蛋白在系统性红斑狼疮患者血清中的浓度升高,与系统性红斑狼疮的正相关。但是第4外显子插入与缺失多态性与系统性红斑狼疮无相关性,该突变不改变Tim-1蛋白在血清中的水平。     

Further polymorphism of the MICA gene.

The MHC class I chain-related (MIC) gene family constitutes an interesting genetic group that is related to major histocompatibility complex (MHC) class I genes and is located within the MHC. The MIC gene products, MICA and MICB, have similar structures to HLA class I molecules. So far over 50 MICA alleles have been reported, which suggests that this genetic system is highly polymorphic. In order to investigate further the extent of MICA polymorphism we have studied exons 2-5 of the MICA gene in over 200 homozygous and heterozygous cell lines. Altogether we have identified 11 new MICA alleles and report 13 new nucleotide variations, one in exon 2, four in exon 3, four in exon 4, two in intron 1, one in intron 4 and one (a deletion) in exon 4. Eight of the 10 exonic variations are non-synonymous. The deletion in exon 4 leads to a frame-shift mutation and the introduction of a repeat of 12 leucine residues encoded by the microsatellite in exon 5. This study provides further evidence that the MICA gene is highly polymorphic. In contrast to MHC class I molecules, the polymorphic sites in MICA are predominantly within the alpha2 and alpha3 domains. The distribution of synonymous and non-synonymous substitutions suggests that there is selection for the polymorphic positions, which therefore define potential functional sites in the protein. We were also able to determine the association between MICA and HLA-B alleles in a number of homozygous cell lines bearing extended haplotypes.     

Further polymorphism of the MICA gene

The MHC class I chain‐related (MIC) gene family constitutes an interesting genetic group that is related to major histocompatibility complex (MHC) class I genes and is located within the MHC. The MIC gene products, MICA and MICB, have similar structures to HLA class I molecules. So far over 50 MICA alleles have been reported, which suggests that this genetic system is highly polymorphic. In order to investigate further the extent of MICA polymorphism we have studied exons 2–5 of the MICA gene in over 200 homozygous and heterozygous cell lines. Altogether we have identified 11 new MICA alleles and report 13 new nucleotide variations, one in exon 2, four in exon 3, four in exon 4, two in intron 1, one in intron 4 and one (a deletion) in exon 4. Eight of the 10 exonic variations are non‐synonymous. The deletion in exon 4 leads to a frame‐shift mutation and the introduction of a repeat of 12 leucine residues encoded by the microsatellite in exon 5. This study provides further evidence that the MICA gene is highly polymorphic. In contrast to MHC class I molecules, the polymorphic sites in MICA are predominantly within the α₂ and α₃ domains. The distribution of synonymous and non‐synonymous substitutions suggests that there is selection for the polymorphic positions, which therefore define potential functional sites in the protein. We were also able to determine the association between MICA and HLA‐B alleles in a number of homozygous cell lines bearing extended haplotypes.     

Identification of MICA alleles with a long Leu-repeat in the transmembrane region and no cytoplasmic tail due to a frameshift-deletion in exon 4

MHC class I chain-related gene A (MICA) is located close to HLA-B gene and expressed in epithelial cells. The MICA gene is reported to be highly polymorphic as are the classical class I genes. To further assess the polymorphism in the MICA gene, we analyzed a total of 60 HLA-homozygous cells for the sequences spanning exons 2-6. In the analysis, four new MICA alleles were identified and six variations were recognized in exon 6. MICA*017, which was identified in three HLA-B57 homozygous cells (DBB, DEM and WIN), differed from MICA*002 in exon 3 and had a guanine deletion at the 3' end of exon 4. MICA*015 identified in an HLA-B45 homozygous cell (OMW) also had the same deletion that causes a frameshift mutation resulting in complete change of the transmembrane region and premature termination in the cytoplasmic tail; these alleles have a long hydrophobic leucine-rich region instead of the alanine repeat in the transmembrane region and terminate at the second position in the cytoplasmic domain. The frameshift deletion was found only in HLA-B45- or -B57-positive panels tested, suggesting a strong linkage disequilibrium between the deletion and B45 or B57. MICA*048, which was different in exon 5 from MICA*008, was identified in an HLA-B61 homozygous cell (TA21), while MICA*00901 identified in HLA-B51 homozygous cells (LUY and KT2) was distinguished from MICA*009 by exon 6.     

中国四个人群中MICA基因多态性研究

目的：了解中国４个人群中ＭＩＣＡ基因第５外显子（ＧＣＴ）ｎ位点的遗传２多态性并从遗传学的角度提供白马藏族起源的初步证据。方法：４１１个无血缘关系个体的血标本或唾液标本分别采自四川平武县白巴藏族、西藏拉萨和云南中甸县藏族、成都地区汉族以及四川茂县羌族。以１对跨越ＭＩＣＡ基因第５外显子ＧＣＴ重复序列区的引物扩增基因组ＤＮＡ,产物用变性聚丙烯酰胺凝胶电泳分离,银染显色分析。结果：在４个群体中均检测出５种已报道的等位片段,并均以Ａ５最常见,在白马藏族、藏族、成都汉族和羌族中的频率分别为０．３２５、０．３４５、０．３９０和０．３１９。Ａ５．１在成都汉族和羌族中占第２位,频率分别为０．２３０和０．２９３,Ａ４和Ａ９在白马藏族和藏族中分别占第２位,频率分别为０．２５４和０．２７２。上述各等位基因分布在４个群体中存在差异,尤其     

Typing for all known MICA alleles by group-specific PCR and SSOP

Major histocompatibility complex class I chain-related gene (MICA) is a recently discovered polymorphic gene in the HLA region expressed mainly by certain epithelial cells, keratinocytes, endothelial cells, fibroblasts, and monocytes. MICA is structurally quite different from the HLA class I genes and is potentially associated with some diseases and with immune response to transplants. Some DNA-based typing techniques have previously been described for MICA including sequence-based typing (SBT) and analysis of single strand conformational polymorphisms (SSCP). In the present experiments we have developed a strategy that allows identification of all 54 MICA alleles described so far, using group-specific polymerase chain reactions (PCR) and sequence-specific oligonucleotide probes (SSOP). To analyze for the polymorphisms in exons 2, 3, and 4 an initial screening with group-specific primers, based on polymorphism at position 69 of exon 2, and at position 615-616 of exon 4, was used to determine four major groups of alleles. Then group-specific PCR amplifications were performed and the amplified DNA was hybridized with the corresponding panels of SSOP. An additional amplification was performed with locus-specific primers and hybridized with a set of SSOP to identify and/or confirm the presence of some of the alleles. Unequivocal MICA typing was achieved for 97 of 103 individuals. Of 54 previously described alleles, only 14 were observed in this population. One unexpected hybridization pattern was observed, and molecular cloning and sequencing confirmed it to be a novel sequence, which was given the local designation MICA-055D. The gene frequencies among 103 unrelated North American Caucasian donors were determined and the linkage disequilibrium between MICA and HLA-B was analyzed.     

Distribution of MICA alleles and haplotypes associated with HLA in the Korean population

The MICA (MHC class I chain-related gene A) is a polymorphic gene located 46 kb centromeric of the HLA-B gene, and is preferentially expressed in epithelial cells and intestinal mucosa. The MICA gene, similar to human leukocyte antigen (HLA) class I, displays a high degree of genetic polymorphism in exons 2, 3, 4, and 5, amounting to 54 alleles. In this study, we investigated the polymorphisms at exons coding for extracellular domains (exons 2, 3, and 4), and the GCT repeat polymorphism at the transmembrane (exon 5) of MICA in 199 unrelated healthy Koreans. Eight alleles were observed in the Korean population, with allele frequencies for MICA*010, MICA*00201, MICA*027, MICA*004, MICA*012, MICA*00801, MICA*00901, and MICA*00701 being 18.3%, 17.8%, 13.6%, 12.3%, 11.1%, 10.8%, 10.6%, and 3.3%, respectively. Strong linkage disequilibria were also observed between the MICA and HLA-B gene-MICA*00201-B58, MICA*004-B44, MICA*00701-B27, MICA*00801-B60, MICA*00901-B51, MICA*010-B62, MICA*012-B54, and MICA*027-B61. In the analysis of the haplotypes of HLA class I genes (HLA-A, B, and C) and the MICA, the most common haplotype was MICA*004-A33-B44-Cw*07, followed by MICA*00201-A2-B58-Cw*0302 and MICA*012-A2-B54-Cw*0102. The MICA null haplotype might be identified in the HLA-B48 homozygous individual. These results will provide an understanding of the role of MICA in transplantation, disease association, and population analyses in Koreans.     

上海汉族人群MICA基因第5外显子微卫星多态性研究

目的 了解上海地区汉族人群ＭＩＣＡ基因第５外显子微卫生多态性分布,以及ＭＩＣＡ基因与其紧密连锁的ＨＬＡ－Ｂ基因位点的关系。方法 用ＰＣＲ－异源双链分析法,对１７５名正常无关个体的ＭＩＣＡ基因第５外显子微卫星多态性的分布进行研究。结果 （１）上海地区汉族人群ＭＩＣＡ基因第５外显子存在５种等位基因,其中ＭＩＣＡ＊Ａ５最为常见（３９．１４％）,其次为＊Ａ５．１（２２．２９％）;（２）ＭＩＣＡ等位基因与Ｈ     

High frequencies of alleles MICA*020 and MICA*027 in Amerindians and evidence of positive selection on exon 3

MICA is a nonclassical polymorphic MHC molecule. We investigated MICA allelic frequencies and MICA-HLA-B-HLA-C haplotypes in Brazilian Amerindians to describe the polymorphism and to extract information about the evolution of MICA gene. Kaingang is the first population described to have a high frequency of MICA*020, found associated with HLA-B*3505-HLA-Cw*0401. Allele MICA*020 probably originated de novo in South America. The Guarani population had high frequencies of MICA*027. Allele MICA*00801 is common worldwide but rare among Amerindians, occurring only because of gene flow. The analysis of the 64 described MICA alleles revealed that in exons 2 and 4, synonymous substitutions are in excess, a result compatible with purifying selection. The opposite was observed for exons 3 and 6 and the excess of nonsynonymous substitutions was significant for exon 3, indicating positive selection. Few of the alleles described so far had exon 6 sequenced, impeding conclusions for the corresponding portion of the molecule. The analysis of the entire gene is required for a better understanding of the evolution of MICA's polymorphism and its functional consequences. This knowledge is of prime importance in view of the increasing awareness of the functional and medical implications of MICA gene variability.     

MICA allele-level typing by sequence-based typing with computerized assignment of polymorphic sites and short tandem repeats within the transmembrane region

MICA genes are located close to, but are structurally distinct from, HLA class I genes and have been found to be associated with some diseases and with immune responses to transplants. We have developed a MICA typing method based on polymerase chain reaction (PCR)/sequence-based typing and a computer program that determines the polymorphisms and distinguishes the GCT repeats in exon 5. One PCR amplification was performed to obtain templates of 2.2 kb including exons 2, 3, 4, and 5 of MICA to be sequenced with two forward and two reverse primers. Overlay of nucleotide sequencing signals resulting from presence of different GCT repeats in exon 5 antisense from two different MICA alleles can be identified by a computer-based analysis of the combined signal string containing the 35 bases. Eighteen reference samples from the 10th International Histocompatibility Workshop with known MICA alleles, as more recently determined, were tested and the concordance was 100% with the previous typing. In addition, 46 samples from kidney or heart transplant recipients and donors were analyzed for their MICA typing by this approach. Results demonstrated that the majority of samples were MICA heterozygous. The most common allele was MICA*00801/A5.1 (44.7%), which was consistent with previous reports. Three samples manifested ambiguous results, either because of polymorphism in exon 6 which was not tested or because the combination of two alleles gives the same pattern as the other two. The procedure was relatively simple and fast and is presently our method of choice for high-resolution clinical MICA typing.