转基因水稻的研究和应用

植物基因工程的兴起,使特定的外源基因引入植物细胞成为可能。水稻转基因研究是国内外植物分子遗传学研究的热点之一。近十几年来,水稻转基因研究已取得显著进展。综述了水稻基因转化的方法、转基因技术在水稻上的应用及外源基因在转基因后代中的遗传表达的研究进展。     

转基因水稻的研究和应用

植物基因工程的兴起,使特定的外源基因引入植物细胞成为可能。水稻转基因研究是国内外植物分子遗传学研究的热点之一。近十几年来,水稻转基因研究已取得显著进展。综述了水稻基因转化的方法、转基因技术在水稻上的应用及外源基因在转基因后代中的遗传表达的研究进展。     

外源基因转化棉花育种研究的进展与应用

棉花作为重要的经济作物,新品种的选育和应用对于促进棉花生产至关重要。通过转基因技术将外源基因转化棉花,是棉花育种的新手段。尤其是抗逆、抗除草剂、抗虫、抗病和提高棉花品质的转基因技术研究,有助于加速棉花新品种的培育。棉花的转基因技术主要包括农杆菌介导法、基因枪轰击法和花粉管通道法。利用不同的转基因技术在棉花外源基因遗传转化的育种研究中取得了明显成效,探讨外源基因转化棉花育种研究的进展与应用,为新疆陆地棉的转基因育种研究提供重要参考。     

转基因鸡生产的理论和实践

近年来,已成功地将外源基因导入许多动物体内,在提高动物生产率和在免疫学、肿瘤学研究方面做出了巨大贡献,第一个转基因动物是由Ｇｏｒｄｏｎ等于１９８０年培育出的转基因小鼠,转基因动物一词是由Ｇｏｒｄｏｎ和Ｒｕｄｄｌｅ在１９８３年提出的。转基因动物就是指被通过添加或删除一个特殊的ＤＮＡ序列,其遗传结构得到了修饰的动物,其改变了的染色体ＤＮＡ可遗传给后代,通过转基因操作所产生的动物叫做建造动物（ＦｏｕｎｄｅｒＡｎｉ－ｍａｌ）,只有部分建造动物的性细胞整合有外源基因［１］。目前为止,转基因动物多数是采取向受精卵原核中注入ＤＮＡ而获得的。自从Ｓｈｕｍａｎ和Ｓｈｏｆｆｎｅｒ［２］在１９８２年第一次将转基因技术应用于家禽之后,许多学者正致力于这方面的工作。家禽的世代周期短,生产性能高,最适合于转基因技术的应用。但家禽繁殖系统的特殊性导致转基因家禽研究,始终落后于其他动物。     

精子因素对精子载体法制备转基因山羊的影响

精子具有主动结合、转运、整合外源DNA的能力,并在受精时导入卵母细胞,获得转基因动物.精子介导基因转移(sperm-mediated gene transfer,SMGT)是目前获得转基因动物简单而高效的方法之一.精子因素是影响SMGT方法生产转基因动物的重要方面.本论文结合我们的研究针对转染用山羊(Capra hircus)精液的来源、精子质膜完整性、精液品质及发育阶段等精子因素影响精子结合外源DNA和SMGT方法生产转基因山羊的效率进行了论述,并从这些影响因素入手,提出了筛选精子供体、保持精液品质、调控质膜等措施,提高精子转染外源DNA能力和生产转基因动物的效率.     

TSA促进转基因猪体细胞核移植胚胎发育和外源基因表达

不完全的表观遗传重编程是造成转基因克隆动物效率低下的主要原因,组蛋白修饰作为表观遗传修饰的一个重要部分,可以直接影响克隆胚胎的发育和外源基因的表达情况。TSA(Trichostatin A)作为一种组蛋白去乙酰化抑制剂,可以改变组蛋白的乙酰化水平,促进表观遗传重编程,提高克隆动物的效率。同时TSA能改变染色质结构,使转录因子易于与DNA序列结合,促进外源基因的表达。文章确定了TSA处理转基因猪成纤维细胞和核移植胚胎的最佳条件,分别为250 nmol/L、24 h和40 nmol/L、24 h,通过进一步正交实验发现,TSA同时处理供体细胞和克隆胚胎可以显著的促进核移植胚胎的体外发育。此外,无论TSA处理转基因猪成纤维细胞或核移植胚胎,都可以提高外源基因的表达水平。     

精子介导的转基因技术

精子介导的转基因技术是近十几年发展起来的一种新技术。从各个种的实验证明,精子有瞬间吸收外源DNA的能力。这一过程由一系列因子起重要调节作用。一种特异的DNA结合蛋白介导了外源DNA与精子的结合,同时精浆中存在一种因子起抑制两者结合的拮抗作用。CD4分子与外源基因的内化有关。内化的DNA可能与精子核支架结构（nuclear scaffold)结合,并整合或重排。但仍需要大量实验数据进一步证明是否产生真正可遗传的转基因后代,及如何提高转基因效率,以使这一方法得到普遍的推广及应用。     

转基因植物中外源基因的遗传学行为

１９８４年,首次利用农杆菌Ｔｉ质粒将外源基因导人烟草获得成功［１」,随后,转基因禾本科作物在水稻上也获得了成功［２,３］。随着各种遗传转化技术的创立与改进,近十几年来,在许多作物上都获得了转基因植株。植物遗传转化技术在基础研究和应用研究中的价值得到了很大体现。尤其是在应用研究上,植物遗传转化技术与常规的育种技术相比,它以超越种间隔离的特点吸引了广大的分子育种家投入到这方面的研究。迄今为止,许多有应用前景的基因已导入到双子叶植物和单子叶植物,并有少量转基因植物已释放到大田应用［４,５］。我们实验室…     

精子介导的转基因技术

精子介导的转基因技术是近十几年发展起来的一种新技术.从各个种的实验证明,精子有瞬间吸收外源DNA的能力.这一过程由一系列因子起重要调节作用.一种特异的DNA结合蛋白介导了外源DNA与精子的结合,同时精浆中存在一种因子起抑制两者结合的拮抗作用.CD4分子与外源基因的内化有关.内化的DNA可能与精子核支架结构(nuclear scaffold)结合,并整合或重排.但仍需要大量实验数据进一步证明是否产生真正可遗传的转基因后代,及如何提高转基因效率,以使这一方法得到普遍的推广及应用.     

转基因植物发展状况及外源基因在后代中遗传分离研究进展

转基因植物近年来得到迅猛发展。本文综述了转基因植物 ,特别是转基因林木的的发展现状。并从单基因位点孟德尔遗传 ,多基因位点孟德尔遗传以及非孟德尔式遗传三个方面介绍了外源基因在转基因植物后代中遗传分离的研究进展。并就影响外源基因遗传分离的因素进行了讨论。     

转基因动物在microRNA研究中的应用

MicroRNA是一类在转录后水平上调节基因表达的非编码小分子RNA,在生物体生理、病理等过程中发挥重要作用．MicroRNA功能的研究将是未来人们关注的焦点．通过转基因技术建立的多种动物模型在整体水平揭示了基因的功能．近年,以microRNA为研究对象的转基因动物模型数量不断增加,构建策略不断丰富．通过miRNA过表达、敲除及敲减等手段已揭示了miRNA在肿瘤、心血管系统疾病等多方面的作用．转基因动物正成为microRNA研究中不可或缺的工具．     

转基因RNAi技术在动物抗病毒育种中的应用

病毒对动物和人类健康都是极大的威胁,抗病毒疫苗虽然能在一定程度上预防病毒病,但目前几乎还不能对变异的传染病进行抗病毒治疗。尽管RNA干扰研究到目前才短短十几年,其作用机理已基本清楚。RNAi能够非常有效的抑制病毒体内复制,其介导的抗病转基因动物的研究相继取得了阶段性进展,抗疯牛病转基因羊和牛,抗内源性逆转录病毒猪以及抗核型多角体病毒病的转基因家蚕已经成功获得。尽管如此,目前的研究主要还是集中在细胞水平及小鼠模型方面,获得的转基因动物种类和数量有限,但为培育动物抗病毒品种提供了理论依据和技术支撑。随着转基因技术的不断的进步和成熟, RNA干扰技术将成为动物抗病毒育种中最有应用前景的方法之一。     

动物基因敲除研究的现状与展望

基因打靶技术是建立在胚胎干细胞和同源重组技术之上,可对基因组进行定位修饰的实验方法,尤其可以在转基因动物的遗传性状修饰中起到巨大的作用。本文简述了转基因、体细胞克隆和基因打靶的研究历史,以及这些技术对转基因动物制备的影响和展望。     

Transgenic farm animals - A critical analysis

The notion of directly introducing new genes or otherwise manipulating the genotype of an animal is conceptually straightforward and appealing from the standpoints of both speed and precision with which phenotypic changes can be made. Thus, it is little wonder that the imagination of many animal scientists has been captivated by the success others have achieved in introducing foreign genes into mice. Transgenic mice not only exhibit unique phenotypes, but they also pass those traits on to their progeny. However, before transgenic farm animals become a common component of the livestock industry, a number of formidable obstacles must be overcome. In this review we attempt to identify the critical issues that should be considered by both those currently working in the field and those scientists considering the feasibility of initiating a transgenic livestock project. The inefficiency of producing transgenic animals has been well documented. This does not constrain investigators using laboratory animal models, but it has a major impact on applying transgenic technology to farm animals. The molecular mechanisms of transgene integration have not been elucidated, and as a consequence it is difficult to design strategies to improve the efficiency of the process. In addition to the problems associated with integration of new genes, there are inefficiencies associated with collecting and culturing fertilized eggs as well as embryo transfer in farm animals. Transgenic farm animal studies are major logistical undertakings. Even in the face of these practical hindrances, some may be pressured by administrators to embrace this new technology. As powerful as the transgenic animal model system is, currently there are limits to the kinds of agricultural questions that can be addressed. Some uses are so appealing, however, that several commercial organizations have explored this technology. Within the next decade or two, it is likely that many of the technical hurdles will be overcome. Combining new techniques with a better understanding of the genetic control of physiological systems will make it possible to improve the characteristics of farm animals in highly imaginative ways.     

Transgenic animals in inflammatory disease models

Inflammatory diseases affect a significant portion of the population worldwide and have been intensely studied for several decades. The advent of transgenic technology has allowed researchers to study individual gene contributions to the pathogenesis of these diseases. This has been done using standard inflammatory disease models in transgenic animals and by identifying novel models through the spontaneous generation of disease in the transgenic animal. Recent advances have been made in the understanding of rheumatoid arthritis, pulmonary inflammation, multiple sclerosis and inflammatory bowel disease through the use of transgenic animals in models of human inflammatory disease.     

影响动物肉质性状主要候选基因的研究进展

随着分子生物学在动物遗传育种中的应用,对数量性状主效基因的研究成为必然。本文对影响肉质的脂肪酸结合蛋白基因、肥胖基因、leptin 基因、黑素皮质受体基因、脂蛋白脂酶基因、激素敏感脂酶基因的国内外研究状况加以综述。 Progress in Candidate Genes Influencing Meat Quality Traits in Chickens QIU Xue-mei1,3,LI Ning1,DEND Xue-mei2,WU Chang-xin2 1.The National Laboratories for Agrobiotechnology,China Agricultural University,Beijing 100094,China; 2.College of Animal Science and Technology,China Agricultural University,Beijing 100094,China; 3.College of Animal Science and Technology,Heilongjiang August First Land Reclamation University,Mishan 158308,China Abstract:As the molecular biology has been applied in animal genetics and breeding,it is important that we research major genes on quantitative traits for animal breeding by transgenic technology.In this paper,the research advance of FABP genes,obese gene,leptin gene,MCRs genes,LPL gene,HSL gene affecting meat quality in animals are reviewed. Key words：animal; meat quality; candidate gene     

Transgene transmission to progeny by oMt1a-oGH transgenic mice

Most studies utilizing transgenic technology focus on the impact to traits of interest, rather than propagation of the transgene to offspring. In animals containing growth hormone constructs, transgene transmission to progeny follows a Mendelian pattern of inheritance in the first few generations following generation of a founder animal, but decreases in subsequent generations. In the present study, the ovine metallothionein 1a-ovine growth hormone (oMt1a-oGH) transgenic mouse was used to determine whether transgene transmission rate to progeny was affected by overexpression of ovine growth hormone in the transgenic parent. The oMt1a-oGH mouse is a useful model for assessing transgene transmission, as the construct is easily regulatable and transgene inactivation results in a return of plasma GH to basal levels. Male and female hemizygous oMt1a-oGH mice were assigned to 1 of 3 treatment groups: (1) mice never actively expressing the transgene, (2) mice actively expressing the transgene from 3 weeks of age, and (3) mice actively expressing the transgene from 3 to 11 (males) or 3 to 8 (females) weeks of age. Transgenic mice were mated to wild type animals and the resulting progeny were genotyped. Males never actively expressing the transgene passed on the transgene to progeny in a Mendelian fashion, while males actively expressing the transgene transmitted the transgene to a smaller than expected number of progeny. However, following inactivation of the oMt1a-oGH construct in transgenic males, subsequent offspring demonstrated Mendelian inheritance of the transgene. In contrast, females expressing the transgene from 3 to 8 weeks of age were able to pass on the oMt1a-oGH construct in a Mendelian fashion, but females from other treatment groups were not. In oMt1a-oGH males, reduced transgene transmission appears to be due to selection against transgenic gametes. In females, however, selection against the transgenic genotype likely occurs at the embryonic level.     

动物转基因新技术研究进展

动物转基因技术是21世纪发展最为迅速的生物高新技术之一, 它是指通过基因工程技术将外源基因整合到受体动物基因组中, 从而使其得以表达和遗传的生物技术。动物转基因的关键限制因素是转基因效率和基因表达的精确调控。目前有多种转基因技术, 每一种技术各有其优缺点, 仍然需要进一步研究。随着研究的深入, 转基因技术必将在探讨基因功能、动物遗传改良、生物反应器、动物疾病模型、器官移植等领域有广阔的应用前景。文章综述了近年发展的提高转基因效率的生殖干细胞法、提高转基因精确性的基因打靶法、RNA干扰(RNAi)介导的基因沉默技术和诱导多能干细胞(iPS)转基因技术。新的转基因技术为转基因动物的研究提供了更好的平台, 可以加快促进人类医药卫生、畜牧生产等领域的发展。     

Transgenic animals: current and alternative strategies

Transgenic animal technology is one of the most fascinating technologies developed in the last two decades. It allows us to address questions in life sciences that no other methods have achieved. The impact on biomedical and biological research, as well as commercial interests are overwhelming. The questions accompanying this fast growing technology and its diversified applications attract the attention from a variety of entities. Still, one of the most fundamental problems remaining is the search for an efficient and reliable gene delivery system for creating transgenic animals. The traditional method of pronuclear microinjection has displayed great variability in success among species. While an acceptable efficiency in the production of transgenic mice has been attained, the relative low efficiency (<1%) in creating transgenic livestock has become one of the barriers for its application. In the past decades, improvements in producing transgenic livestock have made a slow progression, however, the recent advancement in cloning technology and the ability to create transgenic livestock in a highly efficient manner, have opened the gate to a new era in transgenic technology. Discoveries of new gene delivery systems have created an enthusiastic atmosphere that has made this technology so unique. This review focuses on gene delivery strategies as well as various approaches that may assist the advancement of transgenic efficiency in large animals.     

Transgenic and knockout rodents: Novel insights into mechanisms of body weight regulation

Transgenic animals that over- or underexpress a protein of interest have been used to study obesity development, prevention, and susceptibility to diet-induced obesity such as a high-fat diet. Several transgenic models are resistant to diet-induced obesity including those that overexpress the insulin-sensitive glucose transporter, GLUT4, in adipose tissue only. In this animal there is increased adipose tissue mass but the animal maintains its insulin sensitivity. The overexpression of lipoprotein lipase (LPL) in skeletal muscle and the elimination of a protein kinase A subunit both resulted in lean and obesity resistant animals. By directing the production of the diphtheria toxin A chain to adipose tissue only the resulting animals not only had less adipose tissue mass but were resistant to MSG-induced obesity. Conversely, transgenic models with decreased brown adipose tissue or its function have all resulted in obese animals, highlighting the importance of thermoregulation in body weight maintenance. The use of transgenic technology in the field of obesity has emphasized the regional differences among fat pads as well as the dissimilarity between genders in fuel metabolism. Several transgenic models have separated obesity from insulin resistance allowing the importance of each state to be studied individually. Results using transgenic animals have re-emphasized that obesity is a polygenic disease.