Cx43在造血调控及重建中的作用

目的:采用条件性基因敲除技术构建造血系统间隙连接蛋白43(Cx43)基因敲除(Cx43~(-/-))小鼠模型,并探讨Cx43在维持造血细胞自我更新及功能稳定中的作用。方法:将引进的2对转基因小鼠Cx43 loxP/loxP和Lyz-Cre/+杂交,选取F1雌性子代Cx43 loxP/-_Lyz-Cre/+与雄性Cx43 loxP/loxP合笼回配,提取所获得子代小鼠鼠尾组织基因组DNA,采用PCR方法鉴定小鼠基因型,RT-PCR方法筛选Cx43~(-/-)小鼠,同时分析小鼠不同器官中Cx43基因的表达差异;该类小鼠经5-氟尿嘧啶(5-FU;125 mg/kg)处理,在化疗前及化疗后第5、10和15天经眼球取血分析其血象变化。Cx43~(-/-)及Cx43~(+/+)小鼠予7.5 Gy(~(60)Co-γ)的致死量照射,剂量率1 Gy/min,照射后6 h分别给予事先准备就序的骨髓细胞,每只3×10~6细胞于尾静脉注入,2周后处死小鼠检测造血是否重建:分离股骨切片后,收集骨髓细胞进行细胞表型分析(选用的单抗为CD45R、Gr-1、CD4、 CD8a、TCRαβ、Mac-1、抗sIgM、TER119、Sca-1及CD117);同时进行体外造血细胞集落实验观察造血细胞的体外增殖能力。结果:本研究通过2种转基因小鼠间杂交和回交,成功获得造血系统选择性Cx43基因敲除小鼠;该类小鼠骨髓及外周血细胞无Cx43表达,参与造血的组织,如肝脏和脾脏中Cx43表达也显著下调(P0.01),而心脏和肾脏的Cx43表达则无影响,小鼠成年后外周血象分析并无明显异常,但应急代偿能力下降,经5-FU处理后,其造血功能恢复显著减缓,处理15 d后,Cx43~(+/+)小鼠造血功能已接近正常水平,而Cx43~(-/-)小鼠仍无明显的恢复迹象,血红蛋白、白细胞及血小板仍处低位,2者差别有统计学显著性(P0.01);体外集落试验也证实Cx43~(-/-)小鼠造血干/祖细胞的增殖能力下降,其CFU-GM或CFU-E集落数均明显少于Cx43~(+/+)小鼠(P0.01),但流式细胞术结果显示,Cx43~(-/-)小鼠骨髓中Lin~-/c-Kit~+/Sca-1~+细胞亚群数量与Cx43~(+/+)小鼠相比差异并无统计学显著性;Cx43~(-/-)小鼠在化疗或移植后其骨髓造血功能重建均延迟,且化疗15 d后骨髓切片及涂片均证实其骨髓中造血细胞增生程度明显降低,脂肪组织显著增多,而且T、B细胞发育也有异常。此外,其外周血中CD4~+CD8~+细胞比例比野生型小鼠增多(P0.05),但CD4~+T细胞显著减少(P0.01),尤其是TCRαβ亚群细胞减少最为明显(P0.01)。同样,Cx43~(-/-)小鼠外周血中CD45R~+sIgM~-细胞亚群比例与野生型小鼠相比显著减少(P0.01)。结论:骨髓中Cx43基因表达在造血干/祖细胞发育(尤其是应急状态时)具重要作用,敲除Cx43基因后造血干/祖细胞增殖减缓,造血及免疫重建功能受损。     

信号转导和转录激活因子6基因多态性与湖北汉族人变应性哮喘的相关性研究

目的　探讨信号转导和转录激活因子 (STAT) 6基因 3′非翻译区G2 96 4A位点多态性和第一外显子GT串联重复序列遗传多态性与湖北汉族人变应性哮喘易感性的关系。方法　用聚合酶链反应 限制性片段长度多态性 (PCR RFLP)技术检测STAT6基因G2 96 4A位点多态性 ;用聚合酶链反应 短串联重复多态性 (PCR STR)技术对STAT6基因第一外显子微卫星进行分型 ,并将PCR产物克隆及测序鉴定 ;采用病例 对照法研究了 1 35例变应性哮喘患者和 1 0 9例对照。结果　 ( 1 )湖北地区汉族人群STAT6基因G2 96 4A位点基因型以GA型最为常见 ;哮喘组与对照组STAT6基因G2 96 4A位点的等位基因频率和基因型频率GG、GA、AA之间差异无统计学意义 (P >0 .0 5)。 ( 2 )STAT6基因第一外显子微卫星多态性共检出GT串联重复次数为 1 3、1 4、1 5、1 6的 4种等位基因 ;第一外显子微卫星的多态性检测出 1 3/1 4基因型在哮喘患者组和正常对照组相比差异具有统计学意义(P =0 .0 0 1 4 )。 ( 3)STAT6基因第一外显子GT二核苷酸串联重复序列多态性中 1 3 GT重复等位基因与 2 96 4A变异体之间存在连锁不平衡 (P =0 .0 0 0 0 2 1 8)。结论　STAT6基因 3′非翻译区G2 96 4A位点多态性与湖北汉族人哮喘易感性无明显相关性 ;第一外显子GT二核苷酸串联重     

人可溶性IL-6R基因在COS7细胞中的表达及活性分析

目的在ＣＯＳ７细胞中表达具有生物学功能的人可溶性ＩＬ－６Ｒ（ｓＩＬ－６Ｒ），作为研究ｓＩＬ－６Ｒ结构与功能关系的基础。方法首先利用ＰＣＲ技术扩增出人可溶性ＩＬ－６Ｒ（ｈｓＩＬ－６Ｒ）编码基因片段，并重组入克隆载体ｐＡＬＴＥＲ－１。通过基因序列分析确定了目的基因的核苷酸序列，并进一步构建了由ＳＶ４０晚期启动子和ＨＣＭＶ早期启动子控制的表达质粒ｐＳＶＬ６Ｒ和ｐＣＭＶ６Ｒ。用脂质体介导的方法将表达质粒转染ＣＯＳ７细胞，并分别在ｍＲＮＡ水平（斑点杂交）和蛋白水平（ＥＬＩＳＡ和Ｗｅｓｔｅｒｎ－ｂｌｏｔ）检测ｓＩＬ－６Ｒ基因在ＣＯＳ７细胞中的表达。在７ＴＤ１，ＬＴ１２两种ＩＬ－６反应细胞系上检测转染细胞上清（含ｓＩＬ－６Ｒ）的生物学活性。结果在ｍＲＮＡ水平和蛋白水平分别检测到ｓＩＬ－６Ｒ基因在ＣＯＳ７细胞中的表达，表达产物分子量约为５００００。表达产物在７ＴＤ１，ＬＴ１２细胞系上检测到明显的生物学活性。结论天然ｓＩＬ－６Ｒ基因在ＣＯＳ７细胞中的成功表达为进一步制备ｓＩＬ－６Ｒ突变体及其结构与功能关系的研究奠定了基础     

Mediastinal large-cell lymphoma with sclerosis

Summary The Southern blot hybridization technique has been applied to study the configuration of immunoglobulin and T-cell receptor genes in 6 cases of the so called mediastinal large cell lymphoma with sclerosis. This lymphoma has been recently recognized as a separate entity among non-Hodgkin lymphomas mainly affecting young adult patients. The B-cell origin of this neoplasm was suggested by means of immunohistochemical analysis. However, the immunophenotypical B-cell related markers used do not always exhibit lineage fidelity. The Southern blot analysis demonstrated the presence of unique heavy and k-light chain immunoglobulin gene rearrangements, establishing genotypically their B-cell origin.This work was supported by the Associazione Italiana per la Ricerca sul Cancro, Milano, Italy, and Progetto finalizzato Oncologia (contratto n^o 86.00461.44), CNR, Rome, Italy. Aldo Scarpa and Maurizio Lestani are supported by a Scholarship from the Associazione Italiana per la Ricerca sul Cancro, Milano, Italy     

超抗原金黄色葡萄球菌肠毒素基因B的原核表达

目的构建重组pET-30a-SEB原核表达载体,转化感受态大肠杆菌BL-21(DE3),诱导表达超抗原金黄色葡萄球菌肠毒素B(staphylococcalenterotoxinB,SEB)。方法利用PCR技术从产SEB的金黄色葡萄球菌标准菌株CMCC-26075基因组DNA中克隆SEB全长序列,将其克隆到pGEM-TEasy载体中并进行测序。构建pET-30a-SEB原核表达质粒,转化感受态大肠杆菌BL21(DE3),异丙基硫代β-D半乳糖苷(isopropyl-beta-D-thiogalactopyranoside,IPTG)诱导表达,经镍离子螯合亲和层析纯化后免疫鉴定。结果PCR获得超抗原SEB基因片段,与克隆载体连接后经测序与文献报道的基本一致;成功构建了pET-30a-SEB原核表达质粒且成功诱导表达出相对分子质量(Mr)约31×103的蛋白。结论成功克隆了seb基因序列,并进行了原核表达和鉴定,获得了SEB蛋白,为后续对超抗原SEB的进一步研究奠定了基础。     

非小细胞肺癌中p16 INK4／CDKN2基因的缺失和点突变

目的为了探讨周期素依赖性激酶４抑制因子基因（ｐ１６ＩＮＫ４）与肺癌发生的关系。方法采用双重ＰＣＲ－ＳＳＣＰ和序列分析方法，对３１例原发性非小细胞肺癌中ｐ１６ＩＮＫ４基因的存在状况进行了研究。结果３例存在ｐ１６基因缺失（３／３１），其中１例整个ｐ１６基因发生缺失，另两例则分别为外显子１和外显子２缺失；ｐ１６基因点突变２例（２／３１），外显子１和外显子２各一例；并发现在这五例基因异常样品中，４例（２例缺失和２例点突变）样品均为淋巴转移的非小细胞肺癌（４／２０）。结论提示ｐ１６基因失活和某些非小细胞肺癌（５／３１）的发生有关，并且可能发生在癌症的晚期。     

Inhibition of HIV-1 expression by HIV-2

HIV-1 and HIV-2 are co-endemic in certain geographic areas. HIV-2 is more weakly pathogenic than HIV-1, and progression to AIDS occurs less frequently and over a longer period of time. Recent epidemiologic studies suggest that individuals infected with HIV-2 have a lower risk of HIV-1 infection. Both immune mechanisms and various modes of viral interference have been proposed to account for these results. Our findings, described in this paper, suggest that HIV-2 inhibits HIV-1 replication. To study the molecular interactions between HIV-1 and HIV-2, proviral clones were transfected alone or in combination into the human T cell line CEM. LTR-CAT indicator constructs were included for the purpose of monitoring viral promoter activity. Viral replication in transfected cells was monitored by p24 antigen capture assay of cell culture supernatants and Western blot analysis of cell extracts. HIV-2 inhibited HIV-1 replication as determined by intracellular and extracellular p24 antigen levels. Similar results were obtained with simultaneous virus infection using HIV-1 and HIV-2, rather than transfections of proviral DNA. Using cotransfection of HIV-1 and HIV-2 LTR indicator gene constructs, the mechanism of inhibition was found to be suppression of the HIV-1 LTR by HIV-2. The inhibitory effect of HIV-2 is not due to Tat-2, but appears to discriminate between the HIV-1 and HIV-2 LTRs based on differences in the Tat activation response element, TAR. These results suggest both a molecular mechanism for HIV-2 interference with HIV-1 replication and a potential molecular approach to therapy.     

Expression of nonclassical MHC class Ib genes

Peptide binding proteins of the major histocompatibility complex consist of the “classical” class Ia and “nonclassical” class Ib genes. The gene organization and structure/function relationship of the various exons comprising class I proteins are very similar among the class Ia and class Ib genes. Although the tissue-specific patterns of expression of these two gene families are overlapping, many class Ib genes are distinguished by relative low abundance and/or limited tissue distribution. Further, many of the class Ib genes serve specialized roles in immune responses. Given that the coding sequences of the class Ia and class Ib genes are highly homologous we sought to examine the promoter regions of the various class Ib genes by comparison to the well characterized promoter elements regulating expression of the class Ia genes. This analysis revealed a surprising complexity of promoter structures among all class I genes and few instances of conservation of class Ia promoter regulatory elements among the class Ib genes.     

PCR 检测产 A、B、E、F 和 G 型肉毒神经毒素梭菌的神经毒素基因

肉毒神经毒素分为Ａ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆ和Ｇ七个血清型，其中Ａ、Ｂ、Ｅ和Ｆ型引起人类肉毒中毒。为此，选取肉毒神经毒素的保守序列设计了一对简并引物，对１８株肉毒梭菌和８株相关梭菌进行了检测，表明该引物可特异扩增Ａ、Ｂ、Ｅ、Ｆ和Ｇ型肉毒梭菌及产Ｅ型肉毒神经毒素的丁酸梭菌，产物为２６４ｂｐ，敏感性达１０ｐｇ细菌ＤＮＡ。采有酚－氯仿抽提法、固相载体捕获法和热裂解法处理产毒菌株，结果表明热裂解法安全、简便、快速，所制模板扩增效果明显。因此，此ＰＣＲ方法可用于快速敏感地检测引起人类肉毒中毒的梭菌。