广东汉族人群TLR2基因的多态性研究

目的:人类Toll样受体2(TLR2)是先天免疫系统中一个重要的病原微生物识别受体。本研究将建立广东汉族人群TLR2基因座位的功能性多态性图谱,为下一步疾病相关性研究打下基础。方法:收集200例健康、无亲缘关系的中国广东汉族人外周血液,随机抽取其中24例样品,对TLR2基因的启动子区、3个外显子以及它们周围的部分内含子序列进行聚合酶链式反应(PCR)扩增和直接测序,找出多态性位点,对剩余176例样品分别用序列特异性引物聚合酶链反应(PCR-SSP)及PCR技术对发现的单核苷酸多态性(SNPs)和插入/缺失(INDEL)多态性位点进行基因分型,分型结果进行Hardy-W e inberg平衡分析、中性进化分析以及连锁不平衡分析。结果:发现5个SNPs位点,其中2个位于启动子区的SNPs是首次发现,位于编码区的3个SNPs位点均为同义突变,频率最高的SNP是rs3804099,其次要等位基因频率为26.3%;在第1外显子区发现1个长度为22bp的INDEL多态位点(-196到-174),其缺失等位基因所占的频率为31.8%。所有多态性位点均符合Hardy-W e inberg平衡。中性检验显示广东汉族人群TLR2基因符合中性进化假说。连锁不平衡分析显示位于调控区的-18945 C/T和-18883 C/G 2位点之间完全连锁,而位于编码区的rs3804099和rs3804100两位点之间紧密连锁。结论:本研究首次建立了汉族正常人群TLR2基因座位的功能性多态性图谱,并研究了其分布频率,发现了一些种族特异性的多态性位点,为今后开展汉族人基因多态性与疾病相关性研究以及人群进化研究提供了重要资料。     

广东地区汉族人群TLR1 基因多态性的测序研究

目的: 人类Toll样受体1(TLR1)在先天性免疫中起着重要作用。本文将着重研究广东地区汉族正常人群中TLR1 基因功能区的单核苷酸多态性(SNPs)图谱和频率分布。方法: 随机收集50例健康、无亲缘关系的中国广东地区汉族人外周血液,对TLR1 基因的启动子区、5'和3'非翻译区、4个外显子区的序列进行PCR扩增和直接测序,找出多态性位点及其频率分布规律。在此基础上对多态性位点进行Hardy-Weinberg平衡分析、中性进化分析和连锁不平衡分析。结果: 共发现17个SNPs以及2个插入/缺失多态位点,其中2个是首次发现的新多态性位点。位于编码区的新SNP位点+1 378 A/G为非同义突变位点,能导致460位丝氨酸(Ser)残基替换为甘氨酸(Gly)残基,并且这个氨基酸残基的替换处于TLR1胞外区的LRR结构域中,从而有可能影响蛋白的识别功能。另外,频率最高的SNPs是+743 A/G和+1 518 A/G,其次要等位基因频率均达到48%。所有多态性位点均符合Hardy-Weinberg平衡。中性检验显示广东汉族人群 TLR1 基因不符合中性进化假说,很可能是其调控区受到平衡选择作用的原因。连锁不平衡分析显示多态性位点-6 912 C/TA、-6 876 C/T、-6 399 C/T和-6 375 C/T之间,-6 847 A/G和-6 737 A/T之间,以及-5 984 -/CT、-5 531 A/G和-5 490 C/G之间完全连锁。结论: 本研究首次报道了汉族正常人群TLR1 基因的功能性多态性图谱,发现了一些种族特异性的多态性位点及频率分布规律,为今后开展汉族人基因多态性与疾病相关性研究打下一定的基础。     

TLR4基因多态性在中国人群中的初步研究

目的检测中国人Toll样受体4(Toll—like receptor 4．TLR4)基因调控区和编码区的单核苷酸多态性(single nucleotide polymorphisms，SNPs)．寻找TLR4基因的遗传标记。方法采用直接测序的方法检测基因的5′区、编码区、部分内含子区和3′区，以确定中国人群中TLR4基因SNP的位置和类型，并用聚合酶链反应-限制性片段长度多态性对重庆汉族样本进行了抽样调查。结果在4．98kb的测序范围内，发现5个新的SNP，3个位于5′区．2个位于3′非翻译区。在重庆地区汉族样本中．两个高频分布SNP的等位基因频率分别是0．266和0．404。结论在TLR4基因新发现的两个高频多态性位点在我国人群中比较常见，可以作为关联分析的遗传标记。     

湖北汉族人群Tim-3基因启动子及编码区的分子突变

目的：检测湖北汉族人群Tim-3基因启动子区和编码区的单核苷酸多态性，寻找Tim-3基因的遗传标记。方法：采用分段扩增直接测序的方法检测60名湖北汉族人Tim-3基因的启动子区、全部的外显子区及部分内含子区，将测序结果与NCBI及HapMap计划库中其他人种的数据进行对比，确定湖北汉族人群Tim-3基因突变的位置、类型和频率。结果：在Tim-3基因启动子区和外显子区共发现9个SNPs，包含5个已报道的SNPs和4个新发现的突变位点。湖北汉族人群中检出的4个SNPsrs4704853、rs10515746、rs4704846、rs9313439与Ft本人分布相似（P〉0．05），与欧洲人及非洲人的分布则有统计学意义（P〈0．01）。结论：湖北汉族人群Tim-3基因的SNPs分布有别于其他人种，可为在汉族人群中研究Tim-3基因与疾病关联提供依据。     

中国汉族人群TNF-α基因启动子区的多态性研究

目的：研究中国汉族人群TNF-α基因启动子区的基因多态性。方法：采用PCR-SBT（PCR Sequencing Based Typing）方法进行TNF-α基因启动子区的多态检测。结果：采用PCR-SBT方法可以成功获得TNF-α基因启动子区的多态性结果并能够发现新的多态性位点；本次研究发现中国汉族人群TNF-α基因启动子区的多态性位点有：-1031、-863、-857、-572、-308、-238、-204和-163，其中-572和-204的多态性位点为首次报道；我国汉族人群该区域的核酸差异性为（11.00±0.46）×10-4，低于非洲人群；与Malawi人群相比，我国汉族人群-1031C、-308A、-238A出现频率较低，而-857T的频率却较高；与Gambian人群相比，-863A和-857T出现频率较高，-308A出现频率较低；我国汉族人群TNF-α基因启动子区的-1031C、-863A、-857T与-572C、-308A、-238、-204C、-163C有相关性。结论：采用PCR-SBT方法可以成功对TNF-α基因启动子区的基因多态性进行研究，我国汉族人群TNF-α基因启动子区的基因多态性可能存在独特的特点。     

中国汉族人CC趋化因子受体-5基因新的突变位点及多态性分析

目的：调查中国汉族人群人类免疫缺陷病毒－1协同受体CC趋化因子受体-5[chemokine (CC)receptor 5,CCR5]编码区的基因多态性位点，为艾滋病的防治提供依据。方法：CCR5编码区用两对引物进行PCR扩增，设计测序引物依次测序，样本数为42份，用DNAstar分析测序结果，寻找单核苷酸多态性（single nucleotide polymorphism,SNP)位点。结果：在编码区共发现6个SNP位点，4个引起氨基酸改变：A184G、G503T、G668A、G999T；1个单碱基缺失，引起移码突变和提前终止。A184G、G503T、G999T3个中国汉族人所特有的SNP位点为首次发现，等位基因频率分别为1．2％，39．0％和9．5％；其中G503T分布明显不符合Hardy-Weinberg平衡。结论：中国汉族人CCR5编码区SNP位点有自己的特点，与高加索人和非洲人明显不同，与日本人也不完全一致。     

中国湖北地区健康人群RAC1基因多态性的测定与分析

目的：探讨人RAC1基因上8个单核苷酸多态性位点的基因型在中国湖北地区汉族健康人群中的分布情况,为进一步研究RAC1基因多态性与相关疾病及药物反应性之间的关系做铺垫。方法：采用实时荧光TaqMan-MGB探针等位基因分型技术测定150例湖北地区健康志愿者的RAC1基因上8个单核苷酸多态性位点的基因型,并采用分片段扩增直接测序方法对上述位点进行抽样验证。结果：所选8个位点均符合Hardy-weinberg 平衡,其中rs10951982与rs9374, rs702482与rs836488位点间高度连锁不平衡,并运用 Heploview 软件筛选出6个 Tag-SNPs：rs10951982、rs6954996、rs6951997、rs12977、rs702482、rs702483。本研究建立的方法能够准确地测定人RAC1基因上的SNP位点的基因分型,所选的人RAC1基因上8个SNP位点在中国湖北地区人群中的最小等位基因频率与Hap Map数据库中北京地区汉族人群、亚洲人群相近,但亦观察到了人种之间的分布差异。结论：所测RAC1基因上8个位点的频率分布在本研究中的湖北人群中未观察到统计学差异,但是与已有数据库中其他人种的MAF比较有较大差异性。     

中国北方汉族人群中载脂蛋白M基因多态性分布特征及连锁不平衡分析

目的研究中国北方汉族人群中载脂蛋白M基因（apolipoprotein M,APOM）多态性分布特征及其连锁不平衡关系。方法采用PCR扩增基因组DNA直接测序法结合PCR-限制性片段长度多态方法对330名中国北方汉族健康人群的APOM基因单核苷酸多态性（single nucleotide polymorphism,SNP）进行分析。结果中国北方汉族人APOM基因存在1号内含子rs805264位点、5号内含子rs707922位点及rs707921位点3个多态位点,不同种族及地区APOM基因SNP差异有统计学意义。APOM基因rs805264位点、rs707922位点及rs707921位点SNP在中国北方汉族人群中呈现明显的连锁不平衡,主要有G-G-C、A-T-A两种单体型。结论APOM基因SNP在中国北方汉族人群中存在显著连锁不平衡。     

中国汉族人群雌激素受体基因多态性及其与血脂关系的研究

目的：研究雌激素受体（ER）基因多态性在中国汉族正常人群中的分布及其与血脂的关系。方法：应用聚合酶链反应（PCR）和限制性片段长度多态性（RFLP）方法，观察118名正常汉族人ER基因型，同时检测血脂并探讨两者的关系。结果：正常汉族人群中ER基因型以xx型、Pp型和Ppxx型出现频率最高，男女间差异不显著，且基因间血脂水平比较差异无显著性（P＞0．05）。与其它种族比较，ER基因型在中国正常人群中的分布与日本、韩国较为接近，而与瑞典、美国、意大利人群中的分布差异显著。结论：ER基因多态性与血脂水平无相关性，但在不同种族间分布有明显的差异，这种差异可能是导致一些疾病在不同种族间的发生、转归和预后不同的遗传因素之一。     

广西人群TLR4基因3′-非编码区单核苷酸多态性的研究

目的通过对TLR4(Toll-like receptor 4)基因3′-非编码区单核苷酸多态性(single nucleotide polymorphism,SNP)基因型和等位基因的研究分析,了解其在广西地区人群的频率分布及其在不同地区、种族之间分布是否存在差异。方法采用DNA测序方法和单碱基延伸PCR技术检测广西地区人群TLR4基因3′-非编码区rs11536889G/C多态性,并比较广西地区人群与人类基因组计划研究的4个人群(欧洲、中国北京、日本、非洲)(http://www.ncbi.nlm.nih.gov/projects/SNP/)以及韩国地区人群SNP分型数据,以分析TLR4基因rs11536889G/C基因型和等位基因在不同地区人群中的分布差异。结果广西地区人群的TLR4基因3′-非编码区rs11536889G/C位点的分布频率在男性、女性组间无差异(P0.05)。与日本、韩国、中国北京地区人群比较分布差异无统计学意义(P0.05);而与欧洲、非洲地区人群比较,分布有显著性差异(P0.05)。结论广西地区人群TLR4基因3′-非编码区单核苷酸多态性与其它地区、种族人群之间存在统计学差异。     

Single nucleotide polymorphisms and haplotypes of TLR6 gene in Chinese Cantonese population

Sequence polymorphisms in the coding region of Toll-like receptor 6 gene were investigated in Chinese Cantonese population. By amplifying and sequencing a 2787 bp segment containing the entire coding region of TLR6 gene of 191 individuals in Chinese Cantonese population, a total of seven single nucleotide polymorphisms (SNP) along with their frequencies were detected. Comparing these data with SNP published in dbSNP database of National Center for Biotechnology Information (NCBI), two SNP (+176T/C and +1408G/T) were firstly reported, and five SNP caused amino-acid substitution. Sixteen haplotypes and their distributions were reconstructed. Linkage disequilibrium analysis and neutrality test were also performed. Comparing with other ethnic populations, Chinese Cantonese displayed obvious differences in TLR6 polymorphism. It may in part reflect the ethnic diversity of pathogen susceptibility and facilitate to develop the disease-association studies as well as population genetics and evolutionary research.     

Genetic polymorphisms of viral infection-associated Toll-like receptors in Chinese population

Toll-like receptors (TLRs) play a pivotal role in an innate immunity system, which controls inflammation responses and further instructs development of adaptive immunity. We enrolled 250 Han Chinese in Taiwan screening for the single nucleotide polymorphisms (SNPs) in TLRs associated with viral infection, including TLR2, TLR3, TLR4, TLR7, TLR8, and TLR9. The 6 SNPs not hitherto identified in Chinese populations, including TLR3 1377 C>T, TLR3 -7 C>A, TLR7 Gln11Leu, TLR7 IVS1+1817 G>T, TLR8 Met1Val, and TLR8 -129 G>C, had minor allele frequencies of 38%, 23%, 22.3%, 3%, 16.0%, and 16.0%, respectively. The frequencies of 2 common SNPs, TLR9, -1486 T>C and 2848 G>A, were 28% and 44%, respectively. As compared with other ethnic populations, Chinese displayed an opposite allele frequency of TLR8 Met1Val and TLR8 -129 G>C to Caucasians and African Americans. In addition, TLR2 Arg677Try, TLR2 Arg753Gln, TLR4 Asp299Gly, and TLR4 Thr399Ile that were apparent in approximately 10% of Caucasians were not detected in Chinese. In conclusion, obvious ethnic differences in TLR polymorphisms may in part reflect the ethnic diversity of host viral susceptibility.     

Toll-like receptor gene polymorphisms are associated with allergic rhinitis: a case control study

ABSTRACT: BACKGROUND: The Toll-like receptor proteins are important in host defense and initiation of the innate and adaptive immune responses. A number of studies have identified associations between genetic variation in the Toll-like receptor genes and allergic disorders such as asthma and allergic rhinitis. The present study aim to search for genetic variation associated with allergic rhinitis in the Toll-like receptor genes. METHODS: A first association analysis genotyped 73 SNPs in 182 cases and 378 controls from a Swedish population. Based on these results an additional 24 SNPs were analyzed in one Swedish population with 352 cases and 709 controls and one Chinese population with 948 cases and 580 controls. RESULTS: The first association analysis identified 4 allergic rhinitis-associated SNPs in the TLR7-TLR8 gene region. Subsequent analysis of 24 SNPs from this region identified 7 and 5 significant SNPs from the Swedish and Chinese populations, respectively. The corresponding riskassociated haplotypes are significant after Bonferroni correction and are the most common haplotypes in both populations. The associations are primarily detected in females in the Swedish population, whereas it is seen in males in the Chinese population. Further independent support for the involvement of this region in allergic rhinitis was obtained from quantitative skin prick test data generated in both populations. CONCLUSIONS: Haplotypes in the TLR7-TLR8 gene region were associated with allergic rhinitis in one Swedish and one Chinese population. Since this region has earlier been associated with asthma and allergic rhinitis in a Danish linkage study this speaks strongly in favour of this region being truly involved in the development of this disease.     

Common human Toll-like receptor 9 polymorphisms and haplotypes: association with atopy and functional relevance

BACKGROUND: Toll-like receptor 9 (TLR9) is a pattern-recognition receptor that detects unmethylated CpG motifs prevalent in bacterial and viral DNA. TLR9 stimulation is a key event after bacterial infection, triggering innate immunity and T-helper type 1 skewed adaptive immunity. Synthetic CpG-oligodeoxynucleotides (CpG-ODNs) represent a promising and novel class of immune adjuvants for allergy treatment, vaccination, and cancer therapy. However, common functional TLR9 gene variants could interfere with the clinical utilization of CpG-ODN in immunotherapy. Recently, a possible association of TLR9 polymorphism C-1237T with asthma has been reported. OBJECTIVE: The aim of the present study was to investigate whether TLR9 polymorphisms or haplotypes have functional relevance and are associated with atopy. METHODS: We genotyped five common TLR9 single-nucleotide polymorphisms (SNPs) in promoter, exon, and intron regions of the gene in 527 healthy blood donors, and estimated four common haplotypes. The total IgE and specific IgE levels against the most common aeroallergens were measured (n=303). IFN-alpha production by plasmacytoid dendritic cells (pDCs) was analysed after stimulation with TLR9 ligand CpG-ODN (n=220). RESULTS: No significant influence of common TLR9 polymorphisms and haplotypes on the total and specific IgE levels was found. Functional analysis of CpG-ODN-induced IFN-alpha did not indicate a significant role for common TLR9 gene polymorphisms in TLR9 function. CONCLUSION: We conclude that common genetic differences in the TLR9 gene exert no major influence on allergy susceptibility, and are unlikely to have on impact on clinical application of CpG-ODNs.     

No association of toll-like receptor 2 polymorphisms with Alzheimer's disease in Han Chinese

Toll-like receptor 2 (TLR2) represents a reasonable functional and positional candidate gene for Alzheimer's disease (AD) as it is located under the linkage region of AD on chromosome 4q, and is functionally involved in the microglia-mediated inflammatory response and amyloid β (Aβ) clearance. In the current study, 7 single nucleotide polymorphisms (SNPs) that span the TLR2 were selected and their associations with late-onset AD (LOAD) risk were assessed in a case-control sample comprising 785 individuals in a Han Chinese population. No significant differences in the frequency of TLR2 alleles, genotypes, and haplotypes in the AD cases were detected compared with the controls. TLR2 gene might not play a major role in the genetic predisposition to late-onset Alzheimer's disease in this population.     

Extensive polymorphism in the porcine Toll-like receptor 10 gene

The great importance of the Toll-like receptors (TLRs) in innate immunity is well established, but one family member--TLR10--remains elusive. TLR10 is expressed in various tissues in several species, but its ligand is not known and its function is still poorly understood. The open reading frame of TLR10 was sequenced in 15 wild boars, representing three populations, and in 15 unrelated domestic pigs of Hampshire, Landrace and Large White origin. Amino acid positions corresponding to detected nonsynonymous single nucleotide polymorphisms (SNPs) were analysed in the crystal structures determined for the human TLR1-TLR2-lipopeptide complex and the human TLR10 Toll/Interleukin 1 receptor (TIR) dimer. SNP occurrence in wild boars and domestic pigs was compared, and haplotypes for the TLR10 gene and the TLR6-1-10 gene cluster were reconstructed. Despite the limited number of animals sequenced in the present study (N = 30), a larger number of SNPs were found in TLR10 than recently reported for TLR1, TLR6 and TLR2. Thirty-three SNPs were detected, of which 20 were nonsynonymous. The relative frequency of nonsynonymous (d(N) ) and synonymous (d(S) ) SNPs between wild boars and domestic pigs was higher in TLR10 than recently reported for TLR1, TLR6 and TLR2. However, the polymorphism reported in the present study seems to leave the function of the TLR10 molecule unaffected. Furthermore, no nonsynonymous SNPs were detected in the part of the gene corresponding to the hinge region of the receptor, probably reflecting rigorously acting functional constraint. The total number of SNPs and the number of nonsynonymous SNPs were significantly lower (P < 0.05) in the wild boars than in the domestic pigs, and fewer TLR10 haplotypes were present in the wild boars. The majority of the TLR6-1-10 haplotypes were specific for either wild boars or domestic pigs, probably reflecting differences in microbial environment and population history.