转基因动物制作、鉴定和应用研究新进展

近来年,-些研究者在原有的转基因动物制作方法基础上作了改进,如逆转录病毒注射MⅡ期的卵母细胞,体细胞核移植技术法,精子与外源基因合并注射卵母细胞作为载体法以及基因打靶法等.此外转基因动物鉴定和应用也取得了突破性进展.     

转基因动物制作、鉴定和应用研究新进展

近年来，一些研究者在原有的转基因动物制作方法基础上作了改进，如逆转录病毒注射MⅡ期的卵母细胞，体细胞核移植技术法，精子与外源基因合并注射卵母细胞作为载体法以及基因打靶法等，此外转基因动物鉴定和应用也取得了突破性进展。     

转基因动物研究新进展

近年来，一些研究者在原有的转基因动物制作方法基础上作了改进，获得了一些新的方法，如逆转录病毒注射MII期的卵母细胞，体细胞核移植技术法，精子与外源基因合并注射卵母细胞作为核体法以及基因打靶法等。此外转基因动物鉴定和应用也取得了突破性进展。     

乳腺生物反应器表达载体和转基因方法的研究概况

动物乳腺生物反应器，属转基因动物研究的范畴，是指通过各种转基因技术，将某种或几种具有重要生物活性的蛋白外源基因在动物乳腺中高效表达，从而在乳腺中生产目的基因产品。与细胞发酵系统相比，乳腺生物反应器的pH、温度、离子强度等由动物自身控制和平衡，其发酵特性可以遗传，生产效率非常高，而且生产的外源蛋白具有翻译后加工     

山羊体细胞核移植研究进展

体细胞核移植是目前生物技术领域的研究热点之一.山羊是转基因动物研制的理想模型,又是畜牧业生产中的一个重要畜种,而且还可以用转基因奶山羊进行乳腺生物反应器的研究等,因此,山羊的体细胞核移植具有较大的研究价值.就山羊体细胞核移植的研究情况进行了概述.     

动物乳腺生物反应器的研究、发展及产业化

动物乳腺生物反应器(mammary gland bioreactor),又称动物个体乳腺表达系统,它属于转基因动物的范畴,其核心内容是通过各种转基因技术,将乳腺组织特异性启动子驱动的外源基因,在动物乳腺组织高效表达,在乳汁中生产目的产品。它是20世纪90年代初才出现的生物技术,通过回收奶就可以提取有重要价值的生物活性蛋白。在一般情况下,这种特异性表达方式更安全、可靠。本文主要简单介绍动物乳腺生物反应器的一些基本情况,以及我国的研究和产业化发展情况。1动物乳腺生物反应器的基本情况1.1定义乳腺生物反应器一般指用重组DNA技术和转基因技术,将…     

利用动物乳腺生物反应器生产人凝血因子Ⅸ

转基因动物乳腺生物反应器是利用动物乳腺特异性启动子调控元件指导外源基因在乳腺中特异性表达,并从转基因动物奶中获 取重组蛋白。利用转基因动物乳腺生物反应器生产人凝血因子Ⅸ是一种新型的生物制药方法且具有广阔的应用前景。本文就转基因动物 乳腺生物反应器生产人凝血因子Ⅸ的载体构建、研究现状以及存在的问题等作一综述。     

转基因动物乳腺生物反应器研究进展

转基因动物乳腺生物反应器是利用动物乳腺特异性启动子调控元件指导外源基因在乳腺中特异性表达 ,并从转基因动物乳汁中获取重组蛋白。近年来 ,生物学和分子生物学研究领域的成就促进了该技术的蓬勃发展 ,并在生产药用蛋白领域展现出广阔前景。本文简要概述了转基因动物乳腺生物反应器的基本概念、原理、特点及应用 ,并重点阐述其研究现状及前景 ,从而探讨其存在的问题     

利用动物乳腺生物反应器生产人凝血因子IX

转基因动物乳腺生物反应器是利用动物乳腺特异性启动子调控元件指导外源基因在乳腺中特异性表达,并从转基因动物奶中获取重组蛋白.利用转基因动物乳腺生物反应器生产人凝血因子Ⅸ是一种新型的生物制药方法且具有广阔的应用前景.本文就转基因动物乳腺生物反应器生产人凝血因子Ⅸ的载体构建、研究现状以及存在的问题等作一综述.     

动物乳腺生物反应器在现代生物制药中的应用

目的基因在乳腺中表达的转基因动物称为动物乳腺生物反应器(mammary gland bioreaetor),又称为动物个体乳腺表达系统.动物乳腺生物反应器出现于20世纪90年代初,它是一项利用转基因动物的乳房代替生物发酵,大规模生产供人类疾病治疗和保健用的生物活性物质或药用珍稀蛋白的现代生物技术,其核心内容是利用乳蛋白基因的乳腺特异性调控成分驱动外源基因在动物乳腺中高效表达,以期通过源源不断地回收乳汁来提取大量有重要药用价值的生物活性外源蛋白.因此,动物乳腺生物反应器在现代生物制药领域中具有广阔的开发前景.     

Transgenic mouse offspring generated by ROSI

The production of transgenic animals is an important tool for experimental and applied biology. Over the years, many approaches for the production of transgenic animals have been tried, including pronuclear microinjection, sperm-mediated gene transfer, transfection of male germ cells, somatic cell nuclear transfer and the use of lentiviral vectors. In the present study, we developed a new transgene delivery approach, and we report for the first time the production of transgenic animals by co-injection of DNA and round spermatid nuclei into non-fertilized mouse oocytes (ROSI). The transgene used was a construct containing the human CMV immediate early promoter and the enhanced GFP gene. With this procedure, 12% of the live offspring we obtained carried the transgene. This efficiency of transgenic production by ROSI was similar to the efficiency by pronuclear injection or intracytoplasmic injection of male gamete nuclei (ICSI). However, ICSI required fewer embryos to produce the same number of transgenic animals. The expression of Egfp mRNA and fluorescence of EGFP were found in the majority of the organs examined in 4 transgenic lines generated by ROSI. Tissue morphology and transgene expression were not distinguishable between transgenic animals produced by ROSI or pronuclear injection. Furthermore, our results are of particular interest because they indicate that the transgene incorporation mediated by intracytoplasmic injection of male gamete nuclei is not an exclusive property of mature sperm cell nuclei with compact chromatin but it can be accomplished with immature sperm cell nuclei with decondensed chromatin as well. The present study also provides alternative procedures for transgene delivery into embryos or reconstituted oocytes.     

Transgenesis may affect farm animal welfare: a case for systematic risk assessment

This paper considers (potentially) harmful consequences of transgenesis for farm animal welfare and examines the strategy of studying health and welfare of transgenic farm animals. Evidence is discussed showing that treatments imposed in the context of farm animal transgenesis are by no means biologically neutral and may compromise animal health and welfare. Factors posing a risk for the welfare of transgenic farm animals include integration of a transgene within an endogenous gene with possible loss of host gene function (insertional mutations), inappropriate transgene expression and exposure of the host to biologically active transgene-derived proteins, and in vitro reproductive technologies employed in the process of generating transgenic farm animals that may result in an increased incidence of difficult parturition and fetal and neonatal losses and the development of unusually large or otherwise abnormal offspring (large offspring syndrome). Critical components of a scheme for evaluating welfare of transgenic farm animals are identified, related to specific characteristics of transgenic animals and to factors that may interact with the effects of transgenesis. The feasibility of an evaluation of welfare of transgenic farm animals in practice is addressed against the background of the objectives and conditions of three successive stages in a long-term transgenic program. Concrete steps with regard to breeding and testing of transgenic farm animals are presented, considering three technologies to generate transgenic founders: microinjection, electroporation and nuclear transfer, and gene targeting including gene knockout. The proposed steps allow for unbiased estimations of the essential treatment effects, including hemi- and homozygous transgene effects as well as effects of in vitro reproductive technologies. It is suggested that the implementation of appropriate breeding and testing procedures should be accompanied by the use of a comprehensive welfare protocol, specifying which parameters to monitor, at which stages of the life of a farm animal, and in how many animals. Some prerequisites and ideas for such a protocol are given. It is anticipated that systematic research into the welfare of farm animals involved in transgenesis will facilitate the use of the safest experimental protocols as well as the selection and propagation of the healthiest animals and, thereby, enable technological progress that could be ethically justified.     

跨膜蛋白66生物信息学分析及其突变体转基因小鼠构建

跨膜蛋白66(TMEM66)是与细胞凋亡以及癌症发生密切相关的重要功能基因,为了在个体水平研究其生物学功能,我们进行了TMEM66基因突变体(TMEM66V)转基因小鼠的构建。本研究通过原核注射法进行转基因操作,将获得的312个受精卵移植到13只代孕母鼠中,运用PCR、Southern blotting对出生的小鼠进行转基因鉴定,对于转基因阳性小鼠通过传代试验研究外源基因是否稳定整合,并通过反向PCR方法研究外源基因的整合方式。结果显示在出生的55只小鼠中有6只为转基因阳性,其中3只转基因小鼠可以稳定传代,表明这些小鼠中外源基因发生了稳定整合。反向PCR检测结果发现外源片段是以串联重复的方式整合到转基因小鼠的基因组中。本研究成功构建了TMEM66基因突变体转基因小鼠,为进一步研究TMEM66基因的功能奠定了基础。     

Establishing a laboratory animal model from a transgenic animal: RasH2 mice as a model for carcinogenicity studies in regulatory science

Transgenic animal models have been used in small numbers in gene function studies in vivo for a period of time, but more recently, the use of a single transgenic animal model has been approved as a second species, 6-month alternative (to the routine 2-year, 2-animal model) used in short-term carcinogenicity studies for generating regulatory application data of new drugs. This article addresses many of the issues associated with the creation and use of one of these transgenic models, the rasH2 mouse, for regulatory science. The discussion includes strategies for mass producing mice with the same stable phenotype, including constructing the transgene, choosing a founder mouse, and controlling both the transgene and background genes; strategies for developing the model for regulatory science, including measurements of carcinogen susceptibility, stability of a large-scale production system, and monitoring for uniform carcinogenicity responses; and finally, efficient use of the transgenic animal model on study. Approximately 20% of mouse carcinogenicity studies for new drug applications in the United States currently use transgenic models, typically the rasH2 mouse. The rasH2 mouse could contribute to animal welfare by reducing the numbers of animals used as well as reducing the cost of carcinogenicity studies. A better understanding of the advantages and disadvantages of the transgenic rasH2 mouse will result in greater and more efficient use of this animal model in the future.     

脂质体转染胚盘细胞制备携pEGFP—C2基因的转基因鹌鹑

利用脂质体转染第X期胚盘细胞的方法将外源质粒pEGFP—C2经脂质体包裹后注射到鹌鹑种蛋X期胚盘下腔,处理种蛋110枚,封口后孵化。出壳9只G0代,出壳率为8．18％。经检验6只鹌鹑中有4只为阳性,阳性率为66．67％。对成年的4只转基因鹌鹑中的1只内脏组织进行PCR分析以及切片荧光检测,证实外源基因在G0代成年鹌鹑组织中成功表达。将3只成年转基因鹌鹑分别与野生型鹌鹑进行杂交,得到G1代阳性率分别为33．96％、20．59％、10％。再将3只成年转基因公母鹌鹑之间进行杂交,得到G,代阳性率分别为10．87％、42．86％。证实利用脂质体转染胚盘细胞制备转基因鹌鹑是可以将外源基因整合到G0代生殖系中,且外源基因能遗传给后代。     

Effects of trichostatin A on in vitro development and transgene function in somatic cell nuclear transfer embryos derived from transgenic Clawn miniature pig cells

The present study was carried out to examine the effects of post‐activation treatment of trichostatin A (TSA), a histone deacetylase inhibitor, on in vitro development and transgene function of somatic cell nuclear transfer (SCNT) embryos derived from Clawn miniature pig embryonic fibroblast (PEF) transfected with a bacterial endo‐β‐galactosidase C gene (removal of the α‐galactosyl (Gal) epitope). SCNT embryos were incubated with or without TSA (50 or 100 nmol/L) after activation, cultured in vitro and assessed for cleavage, blastocyst formation and transgene function. The rate of blastocyst formation was significantly higher in SCNT embryos treated with 50 nmol/L TSA than that in control (P < 0.05), whereas the rate of cleavage and cell number of blastocyst did not differ. Following labelling with fluorescein isothiocyanate‐labelled BS‐I‐B₄ isolectin, the intensity of fluorescence observed on cell‐surface was dramatically reduced in transgenic SCNT blastocyst in comparison with non‐transgenic SCNT blastocyst. However, the reduction of α‐Gal epitope expression in transgenic SCNT blastocyst was not affected by TSA treatment. The results of this study showed that post‐activation treatment with 50 nmol/L TSA is effective to improve in vitro developmental capacity of transgenic SCNT miniature pig embryos without the modification of transgene function.     

基因转化饲草玉米SAUMZ1提高抗寒性的研究

本研究以拟南芥（Arabidopsis thaliana）叶片为材料,用PCR方法成功地克隆了转录因子CBF1基因,并初步对其进行了序列分析,构建了植物表达载体,然后通过农杆菌介导法将CBF1基因转入饲草玉米SAUMZ1（Zea mays）。PCR分子检测表明,外源基因已经插入到玉米草基因组中。不同低温胁迫处理后,转基因植株比对照植株的相对电导率含量低,进一步说明转入CBF1基因后增强了饲草玉米SAUMZ1的抗寒性。     

An efficient strategy for generation of transgenic mice by lentiviral transduction of male germline stem cells in vivo

Background: Male germline stem cells(MGSCs) are a subpopulation of germ cells in the testis tissue. MGSCs are capable of differentiation into spermatozoa and thus are perfect targets for genomic manipulation to generate transgenic animals.Method: The present study was to optimize a protocol of production of transgenic mice through transduction of MGSCs in vivo using lentiviral-based vectors. The recombinant lentiviral vectors with either EF-1 or CMV promoter to drive the expression of enhanced green fluorescent protein(e GFP) transgene were injected into seminiferous tubules or inter-tubular space of 7-day-old and 28-day-old mouse testes. At 5 or 6 wk post-surgery, these pre-founders were mated with wild-type C57BL/6J female mice(1.5 to 2.0-month-old).Results: Sixty-seven percent of F1 generation and 55.56 % of F2 offspring were positive for eG FP transgene under the control of EF-1 promoter via PCR analysis. The transgenic pups were generated in an injection site-and age-independent manner. The expression of transgene was displayed in the progeny derived from lentiviral vector containing CMV promoter to drive transgene, but it was silenced or undetectable in the offspring derived from lentiviral vector with transgene under EF-1 promoter. The methylation level of g DNA in the promoter region of transgene was much higher in the samples derived lentiviral vectors with EF-1 promoter than that with CMV promoter,suggesting e GFP transgene was suppressed by DNA methylation in vivo.Conclusion: This research reported here an effective strategy for generation of transgenic mice through transduction of MGSCs in vivo using lentivirus vectors with specific promoters, and the transgenic offspring were obtained in an injection site-and age-independent manner. This protocol could be applied to other animal species, leading to advancement of animal transgenesis in agricultural and biomedical fields.     

Liposome-mediated uptake of exogenous DNA by equine spermatozoa and applications in sperm-mediated gene transfer

REASON FOR PERFORMING STUDY: Sperm-mediated gene transfer has been reported as a method for production of transgenic animals in a variety of species, and this technique represents a possible method for production of transgenic equids. OBJECTIVES: To evaluate the uptake of exogenous DNA (enhanced green fluorescent protein; pEGFP) by equine spermatozoa and to assess the ability of transfected spermatozoa to introduce this transgene into early equine embryos. METHODS: To evaluate incorporation of pEGFP into equine spermatozoa, washed spermatozoa were incubated with 32P-pEGFP, with or without lipofection. Spermatozoa were also transfected with fluorescently-labelled DNA (Alexa647-pEGFP) and changes in sperm viability and DNA uptake were assessed. Mares were inseminated with pEGFP-transfected spermatozoa and embryos recovered. Expression of pEGFP was assessed by epifluorescence microscopy of embryos, and the presence of pEGFP DNA and mRNA was assessed by PCR and RT-PCR, respectively. RESULTS: Liposome-mediated transfection increased the incorporation of 32P-pEGFP into spermatozoa compared to controls. Flow cytometric evaluation of spermatozoa after transfection with Alexa647-pEGFP revealed a linear increase in the proportion of live, Alexa647+ spermatozoa with increasing DNA concentrations. After insemination with transfected spermatozoa, 8 embryos were recovered. There was no evidence of EGFP expression in the recovered embryos; however, PCR analysis revealed evidence of the pEGFP transgene in 2 of 5 embryos analysed. CONCLUSIONS: The incorporation of exogenous DNA by equine spermatozoa was enhanced by liposome-mediated transfection and this did not adversely affect sperm viability, acrosomal integrity or fertility. Although the EGFP transgene was detected in a proportion of Day 7-10 embryos, there was no evidence of expression of EGFP in these embryos. POTENTIAL RELEVANCE: Sperm-mediated gene transfer offers a potential technique for the generation of transgenic equids.     

转Cecropin B抗菌肽基因柑橘对溃疡病的离体抗性评价

本文对转Cecropin B抗菌肽基因的锦橙植株进行了表达检测以及柑橘溃疡病病原菌的接菌实验。分别用喷雾法和针刺法进行离体接菌实验,用Real-time PCR和Southern blot进一步检测分析了在转基因植株中Cecropin B基因的表达、整合情况。结果显示与喷雾法相比,针刺接种处理的离体叶片开始显症时间短,且发病率高,便于统计分析。针刺接种6天后,大部分转基因株系发病率与非转基因植株无显著差异,其中,PR8、PR11、AAT8 和AAT14株系的发病率分别为67%、63%、68%和54%,显著低于非转基因植株。Real-time PCR表达分析结果表明,转基因株系中Cecropin B基因表达量明显高于对照株系。Southern blot结果显示PR8和AAT14株系中转基因为单拷贝, PR11和AAT8株系中转基因分别为两个拷贝和三个拷贝。实验结果表明转Cecropin B抗菌肽基因提高了对柑橘溃疡病的抗性。