LMP2/LMP7基因编码区多态性及单倍体型与胃癌易感无相关性

目的:探讨中国汉族人群中肿瘤抗原递呈的限速基因LMP2/LMP7单核苷酸多态性与胃癌的遗传易感性关联.方法:提取145例胃癌患者及152例健康献血员外周血基因组DNA,用PCR-RFLP方法检测两组人群中LMP2-codon60/LMP7-codon145两个多态性位点的基因型;并采用PHASE1.0软件构建这两个多态性位点的个体单倍体型,以非条件Logistic回归校正混杂因素,并进行多态性与胃癌患者风险关联的统计学分析.结果:PCR-RFLP检测结果显示:LMP2-codon60与LMP7-codon145处的多态性在中国人群中普遍存在,LMP2/LMP7多态性位点的各自的等位基因频率分布符合Hardy-Weinberg平衡定律;最后的统计分析表明:在145例胃癌患者与152例健康对照人群中LMP2/LMP7两个多态性位点的基因型频率、以及所构建的4个单倍体型频率均没有统计学差异(P值均大于0.05).结论:在中国汉族人群中,LMP2/LMP7基因编码区两个位点的多态性以及单倍体型与胃癌易感无相关性.     

LMP2/LMP7基因多态性与乙型肝炎病毒感染结局的关系

目的:探讨低相对分子质量蛋白酶体(LMP)基因单核苷酸多态性(SNP)与HBV感染结局之间的关联.方法:提取287例HBV持续感染者(包括无症状HBV携带者、慢性乙型肝炎及乙型肝炎后肝硬化患者)及278例健康对照外周血基因组DNA,用PCR-RFLP方法分析LMP2/LMP7基因Codon60/Codon145两个多态性位点的基因型.结果:LMP7基因多态性位点在健康对照与无症状HBV携带者之间的差异有统计学意义(P＜0.05),与携带Gln/Gln基因型者比较,携带Gln/Lys基因型者乙型肝炎患病风险增加3.35倍(95%CI:2.02-5.58),携带Lys/Lys基因型者乙型肝炎患病风险增加3.46倍(95%CI:1.41-8.48),携带至少1个Lys等位基因者(即Gln/Lys和Lys/Lys基因型)乙型肝炎患病风险增加3.37倍(95%CI:2.06-5.52);LMP7基因多态性位点在健康对照与进展性肝炎(包括慢性乙型肝炎和肝硬化)患者之间的差异有统计学意义(P＜0.05),与携带Gln/Gln基因型者比较,携带Gln/Lys基因型者乙型肝炎患病风险增加2.22倍(95%CI:1.48-3.32),携带Lys/Lys基因型者乙型肝炎患病风险增加4.33倍(95%CI:2.15-8.73),携带至少1个Lys等位基因者(即Gln/Lys和Lys/Lys基因型)乙型肝炎患病风险增加2.49倍(95%CI:1.69-3.65);LMP2/LMP7基因多态性位点在无症状HBV携带者与进展性肝炎患者间的差异无统计学意义(p>0.05).结论:LMP7基因可能是无症状HBV携带和进展性肝炎的易感基因:LMP基因多态性与HBV感染的结局可能无明显相关性.     

中国华北地区人群TAP1基因多态性与乙肝关联性的研究

目的探讨华北地区人群TAP1基因SNPs与乙肝发生的关联.方法提取中国华北地区176例乙肝患者及该地区208例健康献血者外周血基因组DNA,用PCR方法扩增TAP1基因包含Codon333、637片段,采用DNA直接测序法检测健康个体基因型,用RFLP明确乙肝患者基因型.并采用PHASE1.0软件构建这两个多态性位点的个体单倍体型.以非条件Logistic回归校正混杂因素,并进行多态性与乙肝风险关联性的统计学分析.结果TAP1基因2个多态性位点在华北地区人群中具有多态性(均为A→G).其中Codon637多态性位点在两组人群中的差异有高度显著性(P＜0.01),较之野生型A/A,杂合型A/G OR=4.68(95%CI=2.99～7.33),纯合型G/G OR=6.34(95%CI=2.49～16.13);Codon333多态性位点在两组人群中无差异(P＞0.05).在这两个位点所构建的单倍体型中,我们研究发现含有AG单倍体的个体在两组人群中具有高度差异(P＜0.01),OR=19.85(95%CI=8.33～47.31).结论TAP1基因Codon637位点的多态性对于乙肝的发生有着显著的易患关联,其杂合、纯合形式分别增加乙肝患病风险4.68倍和6.34倍.而具有AG单倍体的个体对于乙肝的发生具有更强的易感关联,其增加乙肝患病风险约为19.85倍.     

上海地区汉族人群抗凝血酶基因多态性与肺血栓栓塞症风险的相关性研究

目的 探讨上海地区汉族人群抗凝血酶(antithrombin,AT)基因多态性与肺血栓栓塞症(pulmonary thromboembolism,PTE)风险的相关性.方法 采用病例对照研究的方法,选取91例上海地区汉族PTE患者作为病例组和87例上海汉族体检健康者作为对照组.通过对AT基因的外显子Ⅰ的5ˊ端前核苷酸序列-150～+68及内含子Ⅰ中核苷酸序列+300～+700进行测序,测得2个多态性位点,分别为+320C/T和+645G/A.运用聚合酶链反应-限制性内切酶片段长度多态性技术检测上述2个位点的基因型,并利用SHEsis软件构建其单倍体型,进行单倍体型与PTE风险关联的统计学分析.结果 ①研究发现上海地区汉族人群AT基因2个单核苷酸多态性位点的基因型频率及等位基因频率PTE组与对照组之间差异无统计学意义.②研究发现上海地区汉族人群AT基因共有4种单倍体型CA、CG、TA、TG,这4种单倍体型频率在PTE组分别为51.26(28.2%)、71.74(39.4%)、1.74(1.0%)、57.26(31.5%);对照组分别为59.00(33.9%)、68.00(39.1%)、0.00(0.0%)、47.00(27.0%),PTE组与对照组单倍型频率差异无统计学意义.D'>0.9,上海地区汉族人群AT基因2个多态性位点间存在高度连锁不平衡.结论 上海地区汉族人群AT基因多态性位点与PTE易感性不存在明显相关,AT基因2个位点多态性不是上海地区人群PTE发病的高危因素.     

甘露糖结合凝集素(M B L)基因多态性与中国汉族肺结核易感性的研究

背景:MBL基因据认为在人类抗结核(TB)感染天然免疫应答中发挥作用.目的:探讨MBL基因多态性与中国汉族人群结核感染关联的可能性.设计:共有152名男性肺结核病人和293名健康男性对照纳入本研究.联合应用引物序列特异性PCR(PCR-SSP)和序列特异性寡核苷酸探针杂交(PCR-SSOP)方法对MBL基因六个单核苷酸多态性(SNPs)位点(A/B,A/C,A/O,H/L,Y/X和P/Q)进行基因型或单倍体型在病例组和对照组的分布进行比较,并进行非条件logistic回归分析.结果:当单独考虑时,5个位点的基因型和单倍体型与发病均无显著相关.然而,当重新分组后,和YA组相比,编码低水平MBL的XB单倍体组在病例组中有很高的出现频率(OR=1.57,95%CI:1.02-2.41,P＜0.05)结论:虽然低水平XB单倍型组在中国汉族人群肺结核感染中为一较弱的危险因素,但MBL多态性和肺结核之间的关联没有观察到令人信服的证据.     

VEGF基因-460T/C与-634G/C多态性位点单倍型与ACI易感关联研究

目的 探讨血管内皮细胞生长因子(VEGF)基因启动子区-460T/C与-634G/C多态性位点单倍型在中国汉族人群中与动脉粥样硬化性脑梗死(ACI)的关联.方法 采用PCR-限制性片段长度多态性技术(PCR-RFLP)检测165例ACI患者和198例健康对照者VEGF基因-460T/C与634G/C多态性.并利用PHASE2.3软件构建其单倍体型,以非条件Logistic回归校正混杂因素,并进行单倍型与ACI对患者及其他风险因素的统计学分层分析.结果 VEGF基因-460T/C与-634G/C多态性位点的基因频率分布符合Hardy·Weinberg平衡定律;VEGF基因-460C与-634C组成的C-C单倍型频率在两组人群中的比较有显著性差异,P=0.002,OR=3.86;分层分析中发现:合并高血压(P<0.001,OR=4.16)、高脂血症(P<0.001,OR=6.42)的患者其易感性更为显著.结论 VEGF基因启动子区-460T/C与-634G/C多态性位点组成的单倍型C-C与ACI有着明显的易感关联,而合并有高血压或者高脂血症的患者使易感性关联更为增强.     

肺结核患者肿瘤坏死因子-α基因多态性的研究

目的通过病例-对照研究,探讨肿瘤坏死因子-α(TNF-α)基因启动子区-238A/G、-308A/G位点单核苷酸多态性(SNP)与肺结核病的关系。方法采用序列特异性引物PCR(PCR-SSP)及测序技术检测深圳地区汉族人群肺结核患者200例及健康对照者197例TNF-α启动子区-238A/G、-308A/G位点基因多态性。采用直接计数法计算各组基因型频率及等位基因频率,并进行χ2检验;采用SHEsis软件进行单倍型分析。以P值0.05为具有统计学意义。结果2组人群TNF-α启动子区-238A/G、-308A/G位点基因型及等位基因分布频率差异无统计学意义(P0.05);两位点各种单倍型在2组间分布差异无统计学意义(P0.05)。结论TNF-α启动子区-238、-308位点基因多态性与中国汉族人群肺结核病易感性未见关联。     

中国部分汉族人群中I L-6基因启动子-572G/C多态性与HBV感染易感性的关系

目的: 探讨中国人群中IL-6基因启动子中单核苷酸多态性与HBV感染的遗传易感性关联.方法: 提取160例HBV感染者及212例健康献血者外周血基因组DNA, 用PCR-RFLP方法检测两组人群中G-174C、G-572C和G-597A三个多态性位点的基因型. 性别、吸烟、饮酒以及Hardy-Weinberg等采用Chi-square Test检测,多态性与HBV感染者风险关联及亚组关联的统计学分析采用非条件Logistic回归并同时校正混杂因素.结果: PCR-RFLP检测结果显示: IL-6基因启动子中G-174C和G-597A两个位点在中国人群中不存在多态性, 而G-572C处的多态性在人群中普遍存在, 其多态性位点等位基因频率分布符合Hardy-Weinberg平衡定律. 统计分析表明该位点的多态性在两组人群中有明显的差异(G/C vs G/G, OR = 2.65, P<0.05;C/C vs G/G,OR = 3.31, P<0.05);亚组分析中表明<30岁的年龄组中差异显著(G/G vs G/C或C/C, OR =16.92, P<0.05).结论: 在中国汉族人群中, IL-6基因启动子中-572处的多态性对于乙型肝炎的发生有着显著的易患关系, 同时年龄对于这种易感关联有着协同作用.     

MBL基因多态性与新疆汉族人群结核病易感性的研究

目的探讨MBL基因多态性与新疆汉族人群结核病高发的关系。方法采用病例-对照研究方法和引物序列特异性PCR扩增（PCR-SSP）技术对新疆地区的231例肺结核患者和226例健康志愿者的MBL基因H/L、P/Q和A/B 3个多态性位点进行基因及单倍体分型,比较各等位基因及单倍体型的频率（f）,并计算优势比（OR）。结果对照组MBL基因AA基因型频率显著高于肺结核病例组（χ2=4.576,OR=0.613,P〈0.05）;而肺结核病例组MBL基因AB基因型频率显著高于健康对照组（χ2=4.821,OR=1.673,P〈0.05）。结论 MBL基因AA基因型与新疆汉族人群结核病负相关,其可能为当地汉族人群结核病的抵抗基因;而MBL基因AB基因型与新疆汉族人群结核病相关,其可能是当地汉族人群结核病的易感基因。     

内脏脂肪素基因多态性与宁夏回、汉族2型糖尿病患者的相关性研究

目的 探讨内脏脂肪素基因启动子区-1535 C/T基因多态性与宁夏回、汉族T2DM的相关性. 方法 用PCR-RFLP方法检测210例宁夏回、汉族T2DM患者(T2DM组)及207名健康对照者(NC组)内脏脂肪素启动子区-1535 C/T位点多态性. 结果 两组间及两组内回、汉族内脏脂肪素基因启动子区-1535 C/T基因多态性位点CC、CT、TT3种基因型和等位基因频率差异均无统计学意义(P＞0.05).回族T2DM组TT基因型HDL-C低于CT、CC基因型(P=0.007),汉族T2DM组TT基因型TG较CC、CT基因型高(P=0.026). 结论 内脏脂肪素基因启动子区-1535 C/T位点存在多态性,两组间回、汉族差异无统计学意义;TT基因型可能与T2DM患者血脂异常有关.     

LMP2/LMP7 gene variant: a risk factor for intestinal Mycobacterium tuberculosis infection in the Chinese population

Background and Aims: Low molecular mass protein‐2 (LMP2) and low molecular mass protein‐7 (LMP7) genes play a critical role in foreign antigen processing on the major histocompatibility complex‐I CD8⁺ cytotoxic T‐lymphocyte pathway. This study was designed to investigate whether the sequence variants in the LMP2/LMP7 coding region were associated with intestinal Mycobacterium tuberculosis (M. tuberculosis) infection or with the co‐infection of pulmonary tuberculosis. Methods: A total of 168 patients with intestinal tuberculosis and 235 normal controls were recruited for this study. Two polymorphisms of LMP2 (Arg60–His) and LMP7 (Gln145–Lys) were identified by polymerase chain reaction–restriction fragment length polymorphism method. The associations of the LMP2/LMP7 genotype and haplotype with intestinal M. tuberculosis infection were assessed by using logistic regression analysis. Results: The results revealed that LMP7 position codon 145 Lys/Lys and Gln/Lys alleles in the coding region were associated with the infection of intestinal M. tuberculosis (P = 0.003, odds ratio [OR] = 3.86 and P < 0.001, OR = 2.28, respectively). Meanwhile, the Arg–Lys and Cys–Lys haplotypes exhibited significant relation to the intestinal M. tuberculosis infection (P = 0.006, OR = 1.87; P = 0.021, OR = 1.83, respectively). No significant associations were observed for any of the single‐nucleotide polymorphism genotypes or haplotypes with the co‐infection of pulmonary tuberculosis (P > 0.05). Conclusions: The results indicated that the genetic variant within the LMP2/LMP7 gene would increase the risk of intestinal M. tuberculosis infection.     

EBV LMP2A affects LMP1-mediated NF-kappaB signaling and survival of lymphoma cells by regulating TRAF2 expression

A mechanism used by Epstein-Barr virus (EBV) for in vitro transformation of B cells into lymphoblastoid cell lines (LCLs) is activation of the NF-kappaB pathway, which is largely mediated by the EBV latent membrane protein 1 (LMP1). LMP1 is coexpressed with LMP2A in many EBV-associated lymphoid malignancies. Since inhibition of NF-kappaB leads to apoptosis of EBV-infected LCLs and lymphoma cell lines, we sought to determine whether LMP1 alone, or in combination with other viral proteins, is responsible for initiating NF-kappaB activation in these cells, thereby playing a role in cell survival. We found that suppression of LMP1 by RNA interference results in inhibition of basal NF-kappaB and induction of apoptosis. Unexpectedly, knockdown of LMP2A also resulted in comparable decrease of NF-kappaB activity and apoptosis. We report that LMP2A protein controls the expression of TRAF2 mRNA, which in turn is necessary for signaling by LMP1. Our data contrast with previous studies showing that transfected LMP1 can signal in the absence of LMP2A or TRAF2, and demonstrate that both LMP2A and TRAF2 are required for survival in naturally infected lymphoma cells and LCLs. These results also support LMP1, LMP2A, and TRAF2 as potential therapeutic targets in a subset of EBV-associated lymphoid malignancies.     

Peptidase activities of proteasomes are differentially regulated by the major histocompatibility complex-encoded genes for LMP2 and LMP7.

Recent studies have implicated proteasomes in the generation of the antigenic peptides that are presented on major histocompatibility complex class I molecules to T lymphocytes. Interferon gamma modifies the subunit composition of proteasomes and causes changes in their peptidase activities that should favor the production of peptides with hydrophobic or basic carboxyl termini (i.e., the types found on major histocompatibility complex class I molecules). It has been proposed that these changes in peptidase activity are due to incorporation into proteasomes of the major histocompatibility complex-encoded subunits LMP2 and -7, which are induced by interferon gamma. Here we show by gene transfection into lymphoblasts or HeLa cells that LMP7 increases the capacity (Vmax) of 20S and 26S proteasomes to cleave peptides after hydrophobic and basic residues without affecting hydrolysis after acidic residues. These changes depended on the amount of LMP7 subunits incorporated into proteasomes. Transfection of LMP2 reduced cleavage of peptides after acidic residues, increased hydrolysis after basic residues, and did not affect the hydrophobic activity. Since the activity of the total proteasome population changed after incorporation of only small amounts of LMP2 or -7, these subunits must cause major alterations in peptidase activity. Thus, their expression can account for the changes in proteasome activity induced by inteferon gamma, and these findings lend further support to the proposed roles of LMPs in altering the nature of the peptides generated for antigen presentation.     

Delineation of the subunit composition of human proteasomes using antisera against the major histocompatibility complex-encoded LMP2 and LMP7 subunits.

The products of the Lmp2 and Lmp7 genes located in the major histocompatibility complex (MHC) class II region are postulated to form part of the proteasome complex. This large, multisubunit complex forms the major, nonlysosomal proteolytic machinery for the degradation of endogenous proteins and has been suggested to play a role in the processing of antigens presented by MHC class I molecules. The role of the MHC-encoded subunits within the proteasome has however remained enigmatic. To study this role, we have raised antibodies to recombinant LMP2 and LMP7 proteins. Under denaturing conditions, the anti-LMP7 serum recognizes one subunit of proteasome, whereas the anti-LMP2 serum recognizes two subunits, which may represent different forms of LMP2. The specificity of these sera has been ascertained by a lack of reactivity in T2 cells, which lack both genes. Furthermore under native conditions the anti-LMP2 serum immunoprecipitates a complex that is similar to proteasome but lacks several subunits, including LMP7. Preclearing experiments using this serum and a monoclonal antibody (2-17) specific for the non-MHC-encoded C2 proteasome subunit demonstrate that the complexes recognized by these two sera are distinct and that four subunits are unique to the complex precipitated by the anti-LMP2 serum. Interestingly, the different forms of LMP2 are segregated between these complexes. The relationship of the two complexes is discussed.     

LMP2与LMP7基因多态性与强直性脊柱炎并发虹睫炎易感性关系的研究

目的研究ＬＭＰ基因多态性与强直性脊柱炎并发虹睫炎发病的关系。方法应用ＰＣＲ对正常人和病人进行ＨＬＡＢ２７检测以及ＬＭＰ２和ＬＭＰ７扩增。ＣｆｏＩ进行限制性酶切图谱分析。结果强直性脊柱炎有虹睫炎（ＡＳ＋ＡＡＵ）病史以及单纯虹睫炎（ＡＡＵ）患者ＬＭＰ２基因ＢＢ纯合型较正常人以及强直性脊柱炎（ＡＳ）患者明显增高（Ｐ＜００５）,ＡＳ＋ＡＡＵ患者ＢＢ型ＯＲ＝３６,ＡＡＵ患者ＢＢ型ＯＲ＝５８３。ＬＭＰ７基因多态性无明显差别。结论在我国汉人中,ＬＭＰ２基因多态性与ＡＳ＋ＡＡＵ以及ＡＡＵ发病存在明显相关关系。