制备遗传工程小鼠的技术改进

遗传工程小鼠是当今生命科学领域集成度最高的研究体系之一。特别在“人类基因组计划和小鼠基因组计划”完成后,遗传工程小鼠在制备人类疾病模型、药物开发和评价、基因功能分析以及比较基因组学中发挥着越来越重要的作用。由此,也推动了遗传工程小鼠相关技术的快速发展。就遗传工程小鼠制备的现况、存在的问题以及新策略等相关问题进行了总结。     

实验小鼠在癌症研究中的应用及其进展

小鼠是生物医学研究中使用数量最多的哺乳类实验动物。人类利用小鼠模型进行癌症研究已有100多年的历史,小鼠大量的遗传变异可作为研究人类癌症的借鉴。特别是近年来,培育成功的转基因、基因敲除等遗传工程小鼠模型,使我们对人类癌症发生有了深刻的认识,为评估癌症的诊断方法,革新预防和治疗方案提供了一个很有价值的平台。本文着重介绍了癌症研究中常用的小鼠模型、GEM模型及取得的最新进展等,分析了小鼠肿瘤模型的局限性,并对其发展趋势进行展望。     

慢病毒载体法制备遗传工程猴和小型猪的现状及应用前景展望

较小鼠等啮齿类动物而言,猴和小型猪等大型实验动物在亲缘关系上与人类更为接近,在解剖、生理生化代谢及疾病发病机制等多方面与人类更接近,使它们在复制人类疾病模型,研究疾病发病机制和新药研发等中有无可替代的应用。而制备遗传工程大动物可以更深入地解析人类疾病,并可为器官移植和新药研发提供更充分的实验材料。基于慢病毒介导的转基因方法近几年已越来越多地被用来制备遗传工程猴和小型猪。与传统的原核显微注射方法和体细胞核移植法相比,慢病毒介导的转基因方法转基因效率高,操作更简单。因此,构筑基于慢病毒介导的转基因方法制备遗传工程猴和小型猪的技术平台将对生物医学研究产生巨大推动作用。     

小鼠类胚胎干细胞分离培养及用于制作嵌合体小鼠的实验研究

目的探讨分离小鼠囊胚内细胞群类胚胎干细胞及用于制作嵌合体小鼠的方法及应用价值。方法分离3.5d小鼠囊胚内细胞群的类胚胎干细胞作为供体细胞,通过显微注射方法将分离的类胚胎干细胞注射到供体小鼠的囊胚腔中,再将注射后的囊胚移植到假孕雌鼠的子宫中制作嵌合体小鼠。结果分离36枚囊胚的内细胞群类胚胎干细胞,注射256只昆明小鼠囊胚中,移植32只假孕雌鼠子宫中,获产崽2窝,共12只,其中2只获毛色嵌合体小鼠。结论采用该技术分离所获得的类胚胎干细胞作为供体细胞制作嵌合体小鼠获得成功,该方法为ES细胞介导的转基因动物制作增添了一条新的途径,在同种不同品系的动物改良及遗传病基因治疗中有一定的应用价值,尤其是对未能建立ES细胞系的大动物的遗传工程操作具有一定意义。     

绿色荧光蛋白转基因小鼠模型的建立及胚胎冷冻保种

目的建立绿色荧光蛋白转基因小鼠模型,并采取胚胎冷冻的方法进行保种。方法通过原核显微注射法,把线性化、纯化后的外源基因pEGFP注射入BDF1小鼠受精卵中,胚胎移植给同期发情的假孕受体母鼠,获得子代小鼠。经鉴定对有表达的转基因鼠进行胚胎冷冻保种。结果移植注射胚胎385枚给30只假孕小鼠共出生了306只后代鼠,经PCR和southern blot检测得到5只阳性小鼠。F2代转基因鼠胚胎冷冻240枚胚胎。结论通过显微注射法使外源基因pEGFP在小鼠基因组中得到整合,建立了转pEGFP的转基因小鼠模型。     

TNNT3~（R69H）突变转基因小鼠模型的建立

目的建立TNNT3（R69H）突变转基因小鼠模型。方法构建pEGFP-TNNT3（R69H）转基因构件,通过原核显微注射方法将线性化、纯化后的外源质粒pEGFP-TNNT3（R69H）注射入BDF1小鼠受精卵中,胚胎移植至同期发情的假孕受体母鼠输卵管内,获得子代小鼠。用PCR和Southern blot方法检测子代鼠尾基因组DNA,通过RT-PCR及Western blot的方法检测TNNT3基因表达。结果 8只假孕小鼠共移植注射后的胚胎82枚,出生40只子代鼠,经PCR和Southern方法检测得到5只转基因阳性小鼠。对其子代小鼠进行RT-PCR、Western blot检测结果显示,TNNT3在转基因小鼠心脏和骨骼肌中表达量明显增多。结论通过显微注射法使外源基因pEGFP-TNNT3（R69H）在小鼠基因组中整合,成功建立了TNNT3（R69H）突变转基因小鼠模型。     

Cramp转基因小鼠的构建及鉴定

目的建立系统性表达Cramp转基因模型小鼠,为研究Cramp在衰老中的作用提供模型动物。方法把Cramp cDNA插入系统性表达CMV启动子下游,构建转基因表达载体,显微注射法建立Cramp转基因小鼠。PCR鉴定转基因小鼠的基因型,用RT-PCR和Western blotting方法筛选高表达品系。结果成功构建Cramp cDNA转基因载体,建立了Cramp转基因小鼠,通过RT-PCR和Western blotting方法筛选出3个高表达品系。结论建立了系统表达Cramp转基因小鼠,转入的Cramp基因在骨髓、脾脏、肝脏等组织高表达,为研究Cramp基因在衰老中的作用及机制提供了动物模型。     

PiggyBac转座酶转基因小鼠模型的建立

目的 建立表达PiggyBac转座酶转基因小鼠模型,为研究PiggyBac转座子介导基因修饰在小鼠中的应用提供工具.方法 利用Cytomegalovirus( CMV)启动子驱动PiggyBac转座酶基因的表达,经显微注射法建立C57BL/6J表达PiggyBac转座酶的转基因小鼠.PCR鉴定转基因小鼠的基因型,RT-PCR检测PiggyBac转座酶在小鼠生殖系睾丸中的表达情况.PiggyBac转座酶转基因小鼠活性的检测,是通过与转座子供体转基因小鼠杂交检测供体位置变化来确定的.结果 显微注射产生7只转基因小鼠并能传代,经RT-PCR筛选出一株在睾丸中相对高表达PiggyBac转座酶的转基因小鼠.随后与转座子供体转基因小鼠杂交,子代双阳小鼠与野生型小鼠杂交基因型分离,产生的子代转座子供体单阳性小鼠中具有转座子供体片段的转座反应.结论 成功建立了表达PiggyBac转座酶转基因小鼠动物模型,该模型为PiggyBac转座子技术在小鼠中的应用提供了有价值的工具动物.     

代谢病相关的遗传工程小鼠模型

糖尿病及肥胖症等代谢性疾病已成为影响人类健康的主要疾病,属于多基因所致的代谢综合征,遗传模式复杂多样,至今仍所知甚少。理想的实验动物模型是我们深入了解代谢病病因、遗传及环境因素的必要工具,并且可以用来研究验证新的治疗药物。近年来,已经获得了大量的遗传工程动物模型,包括转基因、基因敲除模型等遗传工程动物,对于代谢性疾病的研究意义重大。本文主要介绍近年来应用较多的糖尿病及肥胖相关的遗传工程小鼠模型遗传特征及应用。     

精子特异性 Sleeping Beauty 转座酶转基因小鼠模型的建立

目的：建立精子特异性表达Sleeping Beauty （ SB）转座酶转基因小鼠模型,为研究SB转座子在小鼠中的应用提供工具。方法克隆精子特异性启动子用以驱动SB转座酶基因的表达,建立精子特异性表达SB转座酶的载体,利用显微注射方法建立以C57BL/6J为背景的精子特异性表达SB转座酶的转基因小鼠。 PCR鉴定首建鼠的基因型,western blot（WB）和免疫组织化学（IHC）检测SB转座酶基因在小鼠生殖腺睾丸中的表达情况,筛选睾丸中高表达SB转座酶的转基因小鼠。结果显微注射方式获得了5只首建小鼠,其中3只能稳定传代,利用WB和IHC成功的筛选出一株在精子中高表达SB转座酶的转基因小鼠。结论成功建立了精子特异性高表达SB转座酶转基因小鼠模型,为将SB转座子作为一种基因工程工具应用于小鼠基因修饰模型的建立提供非常重要的工具资源。     

Genetically Modified Pig Models for Human Diseases

Genetically modified animal models are important for understanding the pathogenesis of human disease and developing therapeutic strategies.Although genetically modified mice have been widely used to model human diseases,some of these mouse models do not replicate important disease symptoms or pathology.Pigs are more similar to humans than mice in anatomy,physiology,and genome. Thus,pigs are considered to be better animal models to mimic some human diseases.This review describes genetically modified pigs that have been used to model various diseases including neurological,cardiovascular,and diabetic disorders.We also discuss the development in gene modification technology that can facilitate the generation of transgenic pig models for human diseases.     

Alterations of stress related proteins in genetically altered mice revealed by two-dimensional differential in-gel electrophoresis analysis

Transgenic, knockout and knockin mice are useful tools for linking specific genes with behaviour and other complex biological processes. However, complications arising due to compensatory changes, genetic background differences and other factors could lead to difficulty in interpreting the resulting changes in phenotype. We have used fluorescence two-dimensional differential in-gel electrophoresis in combination with matrix-assisted laser desorption/ionization-time of flight mass fingerprinting to investigate the possibility that distinct genetic alterations can lead to common protein expression changes in genetically modified mice. Brain proteomes were compared from two transgenic mouse strains (Tg2576 x TgPS1 and Tg2576), two knockout mouse strains (5-HT(7)R -/- and GABA(A)Ralpha5 -/-) and one knockin mouse strain (GABA(A)Ralpha1-H101R). Both of the transgenic models showed an isoform change in the heat shock 70 related protein, mortalin. The knockout and knockin models showed similar changes in mortalin expression along with an alteration of the anti-oxidant protein 2. The observed proteomic alterations indicate that stress-responsive protein pathways may be altered artefactually in all of the mouse models used in this study and highlights an area where caution is needed in interpreting proteomic changes in genetically modified mice.     

An international collaborative study of the effect of active pertussis toxin on the modified Kendrick test for acellular pertussis vaccines

Speculation that the Japanese modified intra-cerebral challenge assay, which is used in several countries for control of acellular pertussis vaccines, depends on the presence of small amounts of active pertussis toxin led to an assumption that it may not be appropriate for highly toxoided or genetically detoxified vaccines. Consequently, at the recommendation of a World Health Organisation AD Hoc Working Group on mouse protection models for testing and control of acellular pertussis vaccine, the effect of pertussis toxin on the modified intra-cerebral challenge assay (modified Kendrick, MICA) was evaluated in an international collaborative study. Results of this study showed that for genetically detoxified vaccines both with and without active pertussis toxin the MICA clearly distinguished mice vaccinated with acellular vaccines from unvaccinated mice and gave a significant dose–response relationship. However, vaccine samples containing active pertussis toxin (5 or 50 ng/single human dose) appeared to be more potent than the equivalent sample without active pertussis toxin. Similar results were also given by two respiratory infection models (intranasal and aerosol) included in the study. The results also indicated that the effect of pertussis toxin may vary depending on mouse strain.     

Using standard nomenclature to adequately name transgenes,knockout gene alleles and any mutation associated to a genetically modified mouse strain

Mice provide an unlimited source of animal models to study mammalian gene function and human diseases. The powerful genetic modification toolbox existing for the mouse genome enables the creation of, literally, thousands of genetically modified mouse strains, carrying spontaneous or induced mutations, transgenes or knock-out/knock-in alleles which, in addition, can exist in hundreds of different genetic backgrounds. Such an immense diversity of individuals needs to be adequately annotated, to ensure that the most relevant information is kept associated with the name of each mouse line, and hence, the scientific community can correctly interpret and benefit from the reported animal model. Therefore, rules and guidelines for correctly naming genes, alleles and mouse strains are required. The Mouse Genome Informatics Database is the authoritative source of official names for mouse genes, alleles, and strains. Nomenclature follows the rules and guidelines established by the International Committee on Standardized Genetic Nomenclature for Mice. Herewith, both from the International Society for Transgenic Technologies (ISTT) and from the scientific journal Transgenic Research, we would like to encourage all our colleagues to adhere and follow adequately the standard nomenclature rules when describing mouse models. The entire scientific community using genetically modified mice in experiments will benefit.     

Simple Databases to Monitor the Generation and Organisation of Transgenic Mouse Colonies

The generation and analysis of transgenic mice has become an important tool to progress our understanding of human and mouse gene function and its association with human genetic diseases. Animal models, based on genetically modified mice, both standard transgenic and knock-out animals, are increasingly being used world-wide. Monitoring of transgenic mouse production and transgenic mouse colonies is required to efficiently manage the resources that are available. Here, I describe three independent FileMaker databases (transgenics, mymouse and cages) that have been developed to track the generation of transgenic mice, the organisation of transgenic mouse colonies and the distribution of mice in cages. These three databases are freely available for academic use.     

The construction of transgenic and gene knockout/knockin mouse models of human disease

The genetic and physiological similarities between mice and humans have focused considerable attention on rodents as potential models of human health and disease. Together with the wealth of resources, knowledge, and technologies surrounding the mouse as a model system, these similarities have propelled this species to the forefront of biomedical research. The advent of genomic manipulation has quickly led to the creation and use of genetically engineered mice as powerful tools for cutting edge studies of human disease research including the discovery, refinement, and utility of many currently available therapeutic regimes. In particular, the creation of genetically modified mice as models of human disease has remarkably changed our ability to understand the molecular mechanisms and cellular pathways underlying disease states. Moreover, the mouse models resulting from gene transfer technologies have been important components correlating an individual’s gene expression profile to the development of disease pathologies. The objective of this review is to provide physician-scientists with an expansive historical and logistical overview of the creation of mouse models of human disease through gene transfer technologies. Our expectation is that this will facilitate on-going disease research studies and may initiate new areas of translational research leading to enhanced patient care.     

Current and future approaches using genetically modified mice in endocrine research

Genetically modified mouse models have been used widely to advance our knowledge in the field of endocrinology and metabolism. A number of different approaches to generate genetically modified mice are now available, which provide the power to analyze the role of individual proteins in vivo. However, there are a number of points to be considered in the use and interpretation of these models. This review discusses the advantages and disadvantages involved in the generation and use of different genetically modified mouse models in endocrine research, including conventional techniques (e.g., overexpression, knockout, and knock-in models), tissue- and/or time-specific deletion of target genes [e.g., Cre-loxP and short interfering (si)RNA transgenic approaches], and gene-trap approaches to undertake functional genomics. This review also highlights the many factors that should be considered when assessing the phenotype of these mouse models, many of which are relevant to all murine physiological studies. These approaches are a powerful means by which to dissect the function of genes and are revolutionizing our understanding of endocrine physiology and metabolism.     

The relevance of genetically altered mouse models of human disease

The impetus to develop useful models of human disease and toxicity has resulted in a number of large-scale mouse mutagenesis programmes. This, in turn, has stimulated considerable concern regarding the scientific validity and welfare of genetically altered mice, and the large numbers of mice that are required by such programmes. In this paper, the scientific advantages and limitations of genetically altered mice as models of several human diseases are discussed. We conclude that, while the use of some such mouse models has contributed considerably to an understanding of human disease and toxicity, other genetically altered mouse models have limited scientific relevance, and fewer have positively contributed to the development of novel human medicines. Suggestions for improving this unsatisfactory situation are made.     

Isolation and Culture of Adult Mouse Cardiomyocytes for Cell Signaling and in vitro Cardiac Hypertrophy

Technological advances have made genetically modified mice, including transgenic and gene knockout mice, an essential tool in many research fields. Adult cardiomyocytes are widely accepted as a good model for cardiac cellular physiology and pathophysiology, as well as for pharmaceutical intervention. Genetically modified mice preclude the need for complicated cardiomyocyte infection processes to generate the desired genotype, which are inefficient due to cardiomyocytes’ terminal differentiation. Isolation and culture of high quantity and quality functional cardiomyocytes will dramatically benefit cardiovascular research and provide an important tool for cell signaling transduction research and drug development. Here, we describe a well-established method for isolation of adult mouse cardiomyocytes that can be implemented with little training. The mouse heart is excised and cannulated to an isolated heart system, then perfused with a calcium-free and high potassium buffer followed by type II collagenase digestion in Langendorff retrograde perfusion mode. This protocol yields a consistent result for the collection of functional adult mouse cardiomyocytes from a variety of genetically modified mice.     

A mouse monoclonal antibody specific for mouse apoB48 and apoB100 produced by immunizing "apoB39-only" mice with mouse apoB48

We have generated and characterized a murine monoclonal antibody (mAb) that binds to both mouse apolipoprotein (apo) B48 and apoB100. We immunized "apoB39-only" mice (mice that synthesize a truncated form of apoB, apoB39, but no apoB48 or apoB100) with lipoproteins containing mouse apoB48 and then used splenocytes from the immunized mice to create hybridomas. We identified a hybridoma, 2G11, that secretes a mAb that binds to mouse apoB48 and apoB100 but not to apoB39. Antibody 2G11 also binds apoB48 and apoB100 from rats and hamsters but not from humans. The mAb recognizes mouse apoB equally in very low and low density lipoproteins and was used to quantify apoB in wild-type, apoE-deficient and low-density lipoprotein receptor-deficient mice and in mice treated with an antisense drug that lowers plasma apoB levels. The antibody will be an important reagent for studying mouse models of atherosclerosis. The study also underscores the utility of genetically modified mice for generating mouse mAbs against mouse proteins.