携带淀粉样前体蛋白瑞典型突变基因转基因小鼠的制备及体内表达研究

目的 建立携带人类淀粉样前体蛋白瑞典型突变（Swedish mutation of amyloid precursor protein,APPSWE)基因的转基因小鼠模型。方法 采用受精卵原核显微注射法，将人类APPSWE转基因导入C57及昆明种小鼠受精卵内，然后将注射后保持完整的受精卵移植到假孕母鼠的输卵管内，然后应用聚合酶链反应（polymerase chain reaction,PCR)、荧光原位杂交及逆转录PCR分析子代小鼠中外源基因的整合及表达情况。结果 注射后卵的存活率和幼子出现率分别为76.62%和10.38%；外源基因整合率为35.29%；共获得6只首建小鼠，已稳定传3代，PCR检测共55只阳性；提取阳性小鼠心、脑、肝、肾组织及骨骼肌以人类APPSWE基因外显子特异的引物进行逆转录PCR分析，结果发现其心、脑组织及骨骼肌中具有人类APPSWE基因的表达。结论 说明携带淀粉样前体蛋白瑞典型突变基因的转基因小鼠模型已制备成功。     

EB病毒膜抗原ELLF1基因转基因小鼠的制备

将Ｅｐｓｔｅｉｎ－Ｂａｒｒ病毒（ＥＢＶ）膜抗原（ＭＡ）ＢＬＬＦ１基因用显微注射法导入昆明种小鼠受精卵的雄性原以制备转基因小鼠模型。共注射受精卵４５０枚，存活２９１枚，植入假孕母鼠的输卵管使之发育，产出仔鼠１２只。     

EB病毒膜抗原BLLF1基因转基因小鼠的制备

将Epstein－Bars病毒（EBV）膜抗原（MA）BLLF1基因用显微注射法导入昆明种小鼠受精卵的雄性原核以制备转基因小鼠模型。共注射受精卵450枚,存活291枚,植入假孕母鼠的输卵管使之发育,产出仔鼠12只。注射后卵的存活率和仔鼠出生率为65％和4％。用PCR法分析显示5只有BLLF1基因整合,整合率为42％。结果表明携带BLLF1基因的转基因小鼠已经制备成功。该转基因小鼠可作为研究EB病毒致病机理,特别是与自身免疫病关系的动物模型。     

弓形虫病患儿静脉血感染豚鼠的实验研究

本实验用２１例弓形虫病患儿的静脉血做豚鼠腹腔内注射接种,７日后阶段取豚鼠耳静脉血查弓形虫ＤＮＡ及弓形虫抗体ＩｇＧ,１８例次,２４只豚鼠获阳性结果,阳性率８５．７％,基本说明ＰＣＲ技术作为对弓形虫病的诊断是可信的检验方法。ＰＣＲ－弓形虫ＤＮＡ阳性是确诊儿童弓形虫病的主要依据。     

人生长激素基因在小鼠体内的表达

本文报道了含人生长激素ｈＧＨ ｃＤＮＡ的重组真核表达质粒的构建及其直接注射后在小鼠体内的表达水平。构建含ＣＭＶ晚期启动子的重组真核基因质表达质粒Ｒｃ／ＣＭＶ ＧＨ ｃＤＮＡ，以阳离子脂质体Ｌｉｐｏｆｅｃｔｉｎ和Ｌｉｐｏｆｅｃｔａｍｉｎｅ分别包裹后直接多点注射于小鼠后肢肌肉组织，并用ＲＴ－ＰＣＲ及免疫放射检测分析法分别在转录水平及蛋白水平检测到了ｈＧＨ ｃＤＮＡ的表达。     

肝脏特异HPPCn转基因小鼠的建立及表型分析

目的建立高表达HPPCn转基因小鼠,为研究该基因在肝癌发生发展中的功能提供研究模型。方法显微注射外源基因pGEM-A1b/his-HPPCn至FVB/N小鼠原核,注射受精卵移植到假孕受体出生个体。PCR和Southern blot鉴定转基因小鼠基因型,Western blot和Realtime-PCR检测转基因阳性和阴性小鼠肝脏HPPCn蛋白表达情况,HE染色和透射电镜观察肝脏病理改变。结果经检测,显微注射共产生2只首建鼠,转入的重组HPPCn基因能在肝脏中特异表达,并能够稳定遗传。转基因小鼠肝脏内HPPCn含量明显增高。转基因后并未对小鼠造成不良影响。结论 HPPCn参与了肝癌发生发展的过程,其在体内的高水平表达,为在体内研究该基因的功能提供了工具。     

慢病毒载体法在制备转基因小鼠模型中的应用

目的改进慢病毒载体法制备转基因小鼠的操作技术,分别从病毒浓缩、受精卵显微注射进针点和如何提高病毒注射效率等方面探讨慢病毒显微注射技术的最佳方案。方法超速离心获得浓缩慢病毒,通过卵周隙显微注射技术感染小鼠受精卵,比较不同注射点显微注射后受精卵存活率及发育情况。结果受精卵1点和5点作为注射点的卵周隙注射组可有效避免注射针与卵膜的直接碰触,减少对受精卵的损伤,胚胎存活率较常规中轴3点作为注射点组显著提高(P<0.01)。适当的病毒滴度和注入量、操作细节、注射针口径等均可影响注射后受精卵存活率和感染率。结论卵周隙显微注射过程中选择适当的注射点以及部分操作的改进,可显著提高受精卵的存活率,为提高转基因小鼠模型的制备效率提供参考。     

HLA-Ⅱ类基因DRα、DRB1*0401转基因鼠模型的建立及体内表达研究

目的　建立携带人HLA-Ⅱ类基因DRα、DRB10401 转基因鼠模型。方法　利用受精卵原核的显微注射技术,将HLA-DRα、DRB10401 两种基因显微注射至C57BL/6×DBA/1 杂交小鼠受精卵中,并移植到假孕受体鼠的输卵管内,然后应用PCR、Southern 印迹杂交和Northern 杂交方法分析子代鼠中基因的整合及表达情况。结果　实验先后有5 只Found 鼠,稳定遗传5 代。经PCR检测有95 只鼠HLA-DR阳性,Southern 印迹杂交出68 只整合含有DRα、DRB10401 混合型的转基因小鼠。经Northern 杂交和RT-PCR检测,其HLA-DR 基因在脾脏和肾脏中均有表达。结论　携带人HLA-Ⅱ类DRα、DRB1401基因的转基因鼠动物模型构建成功     

聚合酶链反应检测流感嗜血杆菌

以一对来自编码流感嗜血杆菌（Ｈｉ）外膜蛋白Ｐ６的基因序列的引物，用聚合酶链反应（ＰＣＲ）扩增Ｈｉ各血清型标准菌株及３０株临床分离菌株，均获阳性结果。而７种对照菌扩增结果均为阴性。用ＰＣＲ反应后琼脂糖凝胶电泳检测的方法，由蒸馏水稀释的菌液及鼻咽深部分泌物模拟标本中分别至少可以检测到３～５个及５０个Ｈｉ菌体。对４０例肺炎患儿鼻咽深部分泌物进行Ｈｉ检测，结果２０例ＰＣＲ阳性，其中１７例培养也阳性。本文作者还首次用ＰＣＲ法从６例肺炎患儿尿标本中检测到了Ｈｉ。研究表明，ＰＣＲ可用于Ｈｉ的检测，该方法敏感、特异、简便、快速，具有良好的应用前景。     

条件化转染MT基因小鼠模型的建立

目的建立四环素诱导调控的MT转基因小鼠模型。为血管瘤试验研究及MT致瘤机理研究奠定基础。方法通过PCR方法从鸡的基因组序列中克隆绝缘子元件；构建四环素诱导调控的条件化转基因质粒，并将其调控元件和受控元件串联成一个载体，在两元件之间插入绝缘子，以减轻两者之间的相互干扰。为提高转基因的表达效率，在转基因盒的上游亦插入绝缘子元件；将MT基因亚克隆至此载体；转基因载体功能行细胞瞬转试验及半定量逆转录-PCR验证后，将其在体外扩增、酶切、回收，行小鼠受精卵原核注射，获得转染MT基因阳性小鼠；强力霉素体外诱导部分阳性鼠MT基因表达，使其具有血管瘤表型。结果绝缘子元件成功克隆；成功构建条件化转基因载体；体外试验证实目的基因的表达受强力霉素的严格调控；通过原核注射，获得5只转基因阳性鼠；2只行体外诱导2月后。1只出现血管瘤表型，逆转录．PCR检测证实MT表达。其余3只阳性小鼠在传代建系中。结论条件化MT转基因小鼠模型成功构建，此小鼠模型能够为血管瘤的试验研究及MT致瘤机理的体内研究提供一定的基础。     

Ubiquitous expression of human SCA2 gene under the regulation of the SCA2 self promoter cause specific Purkinje cell degeneration in transgenic mice

The objective of this work was the generation of an animal model of the SCA2 disease for future studies on the benefits of therapeutic molecules and neuropathological mechanisms that underline this human disorder. The transgenic fragment was microinjected into pronuclei of B6D2F1 X OF1 mouse hybrid strain. For Northern blots, RNAs were hybridized with a human cDNA fragment from the SCA2 gene and a mouse beta-actin cDNA fragment. Monoclonal antibody directed to the N-terminal of the ataxin 2 protein with 22Q was used for Western blot analysis. A rotating rod apparatus was utilized to measure motor coordination of mice. Immunohistochemical detection of Purkinje neurons was performed with anti-calbindin 28K as primary antibody. Ubiquitous expression of the SCA2 transgene with 75 CAG repeats regulated by the SCA2 self promoter was obtained after generation of our transgenic mice. Analysis of transgenic mice revealed significant differences of motor coordination compared with the wild type littermates. Specific degeneration of Purkinje neurons and transgene over-expression in the brain, liver and skeletal muscle, rather than in lungs and kidneys was also observed, resembling the expression pattern of the ataxin 2 in humans.     

Generation and characterization of JSRV envelope transgenic mice in FVB background

Jaagsiekte sheep retrovirus (JSRV) that causes contagious ovine pulmonary adenocarcinoma (OPA) in sheep carries an oncogenic Envelope gene (Env), which is capable of transforming target cells in vitro and in vivo. We cloned full-length JSRV Env cDNA into an expression vector, SPC/SV40, where the transgene was driven by lung-specific surfactant protein C (SPC) promoter, to obtain SPC-JSRV Env construct. SPC-JSRV Env was microinjected into immunocompetent FVB/N mice embryos to generate Env transgenic mice. We obtained two lines of transgenic mice, both of which were capable of developing spontaneous lung tumors from 1 month onwards and the tumor incidence rate was about 56% at the age of 7 months in Env Transgenic line 1 and about 71% at the age of 6 months in Env Transgenic line 2. We were able to correlate higher tumor incidence rate and tumorigenicity in Env Transgenic line 2 to higher level of expression of Env transgene compared to Env Transgenic line 1. Immunohistochemical analysis showed that the tumor was primarily composed of type II pneumocytes where SPC promoter is known to be active similar to natural infection of JSRV in sheep. Analysis of cellular mitogenic signal transduction pathways revealed significant induction of p44/42 ERK pathway in the transgenic mice lungs with tumors compared to the lungs from non-transgenic FVB/N mice. Tumors in our transgenic mice pose similarities to human lung adenocarcinoma and therefore our mice could serve as a model system for evaluating the mechanisms of lung tumorigenesis in vivo.     

A single erythroid-specific DNase I super-hypersensitive site activates high levels of human beta-globin gene expression in transgenic mice

Erythroid-specific DNase I super-hypersensitive (HS) sites that are normally located far upstream of the human beta-globin locus were inserted immediately upstream of a 4.1-kb fragment containing the human beta-globin gene. These constructs (HS beta) and a construct containing the beta-globin gene alone (beta) were microinjected into fertilized mouse eggs, and expression was analyzed in erythroid fetal liver and brain of day-16 embryos that developed. Only 7 of 23 animals that contained the beta gene alone expressed human beta-globin mRNA in erythroid tissue, and the average level of expression per gene copy was 0.3% of endogenous mouse beta-globin mRNA. In contrast, 50 of 51 transgenic mice that contained various HS beta constructs expressed the transgene specifically in erythroid tissue. The average level of expression per gene copy for constructs containing all five upstream HS sites was 109% of endogenous mouse beta-globin mRNA. Constructs that contained a single super-hypersensitive site (HS II beta) expressed 40% as much human beta-globin as mouse beta-globin mRNA per gene copy. These results demonstrate that the HS VI site, normally located downstream of the human beta-globin locus, is not required for high-level expression. Furthermore, the results demonstrate that high levels of human beta-globin gene expression can be obtained in transgenic mice even when a relatively small fragment of DNA (1.9 kb) containing erythroid-specific super-hypersensitive site II (HS II) is inserted upstream of the human beta-globin gene.     

Expression of human F8B, a gene nested within the coagulation factor VIII gene, produces multiple eye defects and developmental alterations in chimeric and transgenic mice.

Factor VIII-associated gene B ( F8B ) is a small human gene of unknown function which is nested within the gene encoding coagulation factor VIII ( FVIII ) in chromosome band Xq28. The sequence of F8B includes the C2 cell adhesion motif of factor VIII, which has also been identified in numerous proteins known to play important roles during development. Here we have constructed both chimeric and transgenic mice expressing normal human F8B to investigate its possible developmental effects. The chimeras produced from embryonic stem cells transfected with normal F8B under control of a cytomegalovirus promoter and selected for neomycin resistance expressed readily detectable levels of F8B mRNA in multiple tissues. They showed growth retardation, microcephaly, reduced longevity and severe ocular defects, and although they were fertile, gave birth to no F8B heterozygous pups. Seven transgenic mouse lines, produced by injection of the transgene into fertilized oocytes, were viable and of normal size but expressed lower levels of F8B mRNA. Strikingly, they showed the same severe eye abnormalities as the chimeras. These defects included anterior segment dysgenesis, absent or abnormal lens, persistence of the primary vitreous, Harderian gland tumors and ectopic pigmented cells, suggesting that migration of neural crest cells might have been perturbed during eye development. In addition, dysplastic retinas and the absence of photoreceptors were observed, providing a mouse model for retinal degeneration.     

HLA and H2 class II transgenic mouse models to study susceptibility and protection in autoimmune thyroid disease

Using single H2 and HLA class II transgenic mice, in the absence of endogenous H2 class II molecules, we have studied the permissiveness of class II molecules for experimental autoimmune thyroiditis (EAT). Resistant strains expressing susceptible class II molecules, H2Ak or HLA-DR3, developed EAT, clearly demonstrating the importance of class II gene inheritance. Polymorphism for HLA-DRB1 was observed, as DR3, but not DR2 or DR4, molecules were permissive for EAT induction with either mouse (m) or human (h) thyroglobulin (Tg). HLA-DQ polymorphism was also detectable, as hTg-induced EAT developed in DQ8+, but not DQ6+, mice. Class II gene interactions leading to reduced EAT severity were observed in H2 transgenic mice, when H2E transgene was expressed in H2A+ mice or H2A molecules were introduced into our novel H2A- E+ transgenic model. Similarly, in DR3+ mice, only the DQ8 transgene reduced EAT severity, depending on both background genes (C57BL/10 or NOD) and Tg species. Based on computer-predicted, class II-binding motifs, potential pathogenic Tg peptides, either unique to hTg (H2A- E+ model) or shared between mTg and hTg (HLA-DR3+ model), were identified. We have also developed a Graves' disease model by immunizing DR3+ mice with TSH receptor DNA. Thus, transgenic models are excellent tools to study human autoimmune thyroid diseases in the context of murine EAT.     

Targeted expression of activated Rac3 in mammary epithelium leads to defective postlactational involution and benign mammary gland lesions

Rac3, a novel member of the Rho subfamily of the small GTPases, is frequently activated in cultured breast cancer cells and has been shown to mediate its effect via the p21-activated kinase (Pak) pathway. In order to evaluate these findings in vivo, we generated transgenic mice that express human constitutively active V12Rac under the control of the mouse mammary tumor virus (MMTV) promoter, which targets the transgene expression to the mammary epithelium. V12Rac3 expression could be detected during the first pregnancy, and the transgenic mammary gland tissues displayed an elevated Pak1 phosphorylation. Although milk proteins, beta-casein and whey acidic protein were expressed and milk fat globules accumulated normally during pregnancy, 60% of transgenic mothers failed to nurse their pups. Surprisingly, although full lactational differentiation was never achieved in transgenic mice, gland involution was incomplete. For 5 days after weaning, involution was normal, but thereafter, epithelial islands characteristic of this early stage of involution persisted for months. The apoptotic index decreased after 5 days, and these glands were associated with increased p38 MAPK phosphorylation. Nine months postpartum, the transgenic mammary glands still demonstrated a large amount of persistent epithelial islands and abnormally large ducts with lymphocyte infiltration, whereas the tissues of non-transgenic controls had returned to their normal 'virgin-like' phenotype. These data show that sustained activation of Rac3 in the mammary epithelium leads to impaired mammary gland physiology and results in the formation of mammary gland lesions.