睾丸注射法制备携带猪PID1基因的转基因兔

目的研究磷酸酪氨酸互作结构域1(PID1)基因与肌内脂肪含量的关系,探究睾丸注射法在转基因动物制备中的可行性。方法将携带猪PID1基因的重组质粒pIRES2-acGFP-PID1与转染试剂共孵育后,对新西兰兔进行了睾丸打点注射试验。对繁殖的F1代个体进行了活体荧光检测、PCR和western blotting检测,以及抽样屠宰进行肌内脂肪含量等检测;将F1代阳性个体互交,繁殖了F2代兔,对其进行了阳性率检测以及肌内脂肪含量检测。结果外源PID1基因和荧光蛋白基因在后代中均成功表达,其中,F1代阳性率为35.88%,F2代阳性率为34.33%;转基因阳性兔与阴性和空白对照兔相比,PID1蛋白表达水平有所增加,肌内脂肪含量有显著提高(P0.05)。结论 PID1基因与肌内脂肪沉积密切相关,同时,进一步证明了睾丸注射法可以用于制备转基因动物,且外源基因可以稳定遗传。     

体内系统转基因新方法

建立了一种全新而高效的制备转基因动物新方法.无需外科手术,将含有绿色荧光蛋白的重组质粒直接多次多点反复注射到雄性ICR小鼠的睾丸内.几周后,上述雄性动物与自然发情的雌性交配,制备转基因动物.经PCR检测、DNA印迹,实验结果表明:F1代小鼠转基因阳性率为41%.经DNA印迹证明:外源基因已经整合到子代转基因动物的基因组内并能遗传给后代.将F1代阳性鼠与正常ICR鼠交配,产生F2代转基因鼠,F2代转基因阳性率37%.上述实验结果表明,建立的体内系统转基因方法简便、高效,适用于大规模制备转基因动物,特别适用于一些大型家畜.     

通过睾丸内注射转染外源DNA在小鼠精子的表达

为研究睾丸内注射外源DNA法生产转基因小鼠(Mus musculus)的可行性,并探讨注射DNA的最佳浓度。将环形的质粒DNA pEGFP-N1与脂质体混合制备DNA-脂质体复合物,按DNA浓度不同分为0.08μg/μl、0.12μg/μl和0.24μg/μl3组,分别注射入成年SPF级昆明小鼠睾丸内,同时设空白对照;每组处理公鼠2只,注射5d后每只与3只成年母鼠同笼,20d后在荧光显微镜下检测公鼠附睾精子,并制作睾丸石蜡切片,检测绿色荧光蛋白(GFP)的表达;PCR法检测各组后代阳性率。结果显示,3组小鼠附睾荧光精子比例分别为9.09%、47.06%和27.78%。3组小鼠的睾丸石蜡切片中均可看到不同强度的GFP表达。后代经PCR检测阳性率分别为17.26%、47.61%和22.11%。本实验证实了睾丸注射法能使外源DNA整合进入精子基因组,并能在自身和后代中得到表达,本研究中外源DNA注射浓度以0.12μg/μl效果为最佳。     

体内外精原干细胞介导大群生产转基因鸡

本研究以重组的绿色荧光蛋白基因为标记,采用公鸡睾丸内转染精原干细胞（spermatogonial stem cells,SSCs）和体外转染SSCs再移植的方法,探索家禽转基因新方法．同时比较了公鸡接受不同剂量外源基因的转基因效率．结果显示：（i）接受外源基因剂量分别为50,100,150和200μg／mL时,48h后睾丸细胞显示绿色荧光的比率分别为4．0％,8．7％,10．2％和13．6％,差异显著（P〈0．05）．睾丸内注射外源基因第25天后,随着时间的增长,精子表达绿色荧光的百分率逐渐提高,到第70天后表达率达到高峰,且趋于稳定,4个剂量组分别为12．7％,12．8％,15．9％和19．1％．差异显著（P〈0．05）;（ii）第70天的睾丸冰冻切片观察,曲精细管周边均有荧光表达;（iii）F1代中,56．2％（254／452）的胚盘表达绿色荧光．活鸡血样PCR检测56．5％（13／23）为阳性,Southern blot检测证明外源基因已整合到鸡基因组;F2代中,53．2％（275／517）的胚盘表达绿色荧光．活鸡血样PCR检测52．9％（9／17）为阳性;（iv）F,代和F2代鸡心、肝、肾和肌肉等组织冰冻切片观察和PCR检测,绿色荧光阳性率在50．0％～66．7％之间;（v）体外SSCs转染外源基因后移植,可在受体公鸡睾丸中生长发育,正常产生精子．后代中,12．5％（8／64）的胚盘表达绿色荧光,活鸡血样PCR检测11．1％（2／18）为阳性．结果证明精原干细胞介导转基因是一种简单、高效、可大群体生产转基因鸡的有效途径．     

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。     

小鼠精子形成各阶段转基因效率的研究

在过去的近30年中,转基因技术在哺乳动物基因表达方面研究的应用已经成为实验生物学及应用生物学领域最为显著的进展之一．传统的制作转基因动物方法有显微注射法、逆转录病毒感染法和胚胎干细胞法等,但每种方法都有其缺陷,限制了其在今后转基因动物研究中的广泛应用．对小鼠体内生殖细胞进行外源基因转染,研究精子形成过程中制作转基因小鼠的效率．首先运用睾丸注射法将被脂质体包裹的绿色荧光蛋白表达载体(pIRES2-EGFP)注射到公鼠睾丸及附睾内,然后根据精子形成的不同阶段,分别于注射后7、16、30和42天与发情母鼠合笼,利用PCR和DNA印迹方法对新生小鼠进行基因组DNA检测．在各阶段所得新生小鼠中PCR阳性率分别为6.82%、0、56.86%和42.86%,DNA印迹检测阳性率分别为6.82%、0、47.06%、34.69%．经活体荧光成像系统及荧光显微镜分析,转基因小鼠呈现绿色荧光表达．通过比较精子生成各阶段转基因效率高低,为以后通过用睾丸内注射法转染雄性生殖细胞高效制作转基因动物提供了理论依据．     

应用荧光原位杂交技术检测人β^E珠蛋白基因小鼠染色体上的整合状态

为将荧光原位杂交技术应用于基因定位研究中,探讨一种能有效地检测转基因动物染色体上外源基因整合状态的实验方法,对小鼠腹腔注射秋水仙素后,取转基因小鼠骨髓制备中期染色体,将传统的FISH方法加以改进,检测外源基因在转基因小鼠染色体上的整合状态。检测结果表明,外源人β^E珠蛋白基因已稳定地整合于小鼠染色体上,FISH能直观地反映外源基因在转基因动物染色体上的整合状态,该方法可对转基因动物及基因转移研究中的外源基因整合反进行染色体定位检测。     

携带HLA-B2704基因转基因小鼠技术的建立

应用显微注射法制备携带HLA B2 70 4基因的转基因小鼠 .对 2 86只昆明小鼠激素注射进行超排卵 ,采集受精卵 ,将含HLA B2 70 4基因的基因组DNA片段 (简称HLA B2 70 4DNA)显微注射到受精卵原核内 ,把注射存活的两细胞期受精卵移入假孕鼠的输卵管内使其发育产生后代 .用PCR方法进行F0代仔鼠及F1代仔鼠的转基因整合的检测 .利用RT PCR检测阳性鼠中的HLA B2 70 4转基因的表达 .采集了 84 11个卵 ,可注射卵 6 6 0 9个 ,其中注射存活的两细胞期受精卵 4 2 77个 ,卵的注射存活率为 6 4 7%.将卵移入 15 3只假孕鼠 ,其中 2 6只怀孕产仔 ,存活 10 1只 .在 10只F0代仔鼠基因组中有HLA B2 70 4基因整合 ,整合率为 9 9%.转基因阳性鼠F0代之间以及与正常鼠之间进行交配 ,产生的F1代仔鼠 78只 ,其中 15只为阳性 .阳性鼠的皮肤、结肠、睾丸和脾脏组织中均有HLA B2 70 4转基因mRNA的表达 .在HLA B2 70 4转基因阳性小鼠中 ,6只小鼠皮肤出现脱毛 ,1只小鼠的足部及足趾明显红肿 ,2只在脱毛同时明显畏光 ,1只出现腹泻 .结果表明 ,成功地建立了HLA B2 70 4的转基因小鼠技术 ,该小鼠类似强直性脊柱炎的小鼠模型 .     

利用卵胞浆精子注射（ICSI）技术生产转基因小鼠

在掌握小鼠ICSI技术的基础上,进行了ICSI技术生产转基因小鼠的研究。来自成年KM小鼠附睾尾的精子,使用未加抗冻剂的HEPES-CZB溶液,在液氮中冻融1次后,用于本实验。解冻精子与DNA混匀1min后,精子头被显微注射到B6D2F1小鼠成熟卵母细胞质中。精子头与pEGFP-N1环状DNA共注射生产的ICSI受精卵,在CZB溶液中培养至囊胚期时,39.1%(9/23)的囊胚表达GFP基因。精子注射后6h,直接移植ICSI受精卵后,7只妊娠受体一共产仔30只,效率为23.8%(30/126)。Southernblot分析其中16只小鼠发现,3只(18.8%)转基因小鼠同时整合了GFP和Neomycin基因,它们全部来自精子和线性DNA混合的实验组(阳性效率为33.3%,3/9),相反,精子与环状质粒DNA共注射生产的7只ICSI后代中,没有检测到外源基因。转基因小鼠整合的外源基因能够传递给它们后代。结果说明,利用ICSI技术可以高效地生产转基因小鼠,宿主基因组可能更容易整合线性化的外源基因。     

睾丸内注射pEGFP-N1体内转染精子并在山羊早期胚胎成功表达

目的探讨睾丸内注射法pEGFP-N1在精细胞的整合和在早期胚胎中表达.方法选择4头本地山羊,双侧睾丸注射不同剂量质粒DNA pEGFP-N1,注射后PCR和Southern杂交检测pEGEP-N1在精子中的整合.结果pEGFP-N1整合到精子基因组中,转染效率最高发生在注射后第40天,转染阳性率最高为81%;绿色荧光蛋白在精子及其体外受精的部分胚胎中表达,胚胎阳性率最高的达66.7%.结论通过睾丸内注射pEGFP-N1能整合进入精子基因组,并能通过体外受精在山羊早期胚胎中表达;睾丸内注射法可能是一种可行、简单并利于推广的制备转基因山羊的方法.     

Production of transgenic mice expressing the goat H-FABP gene by intratesticular injection

The objective of this study was to explore the possibility of obtaining stable transgenic animals by intratesticular injection. The recombinant vector pEGFP-H-FABP expressing the goat heart-type fatty acid binding protein and green fluorescent protein was mixed with liposome complexes and randomly injected into the testes of mice. Testicular section, fluorescence, and DNA detection assays of mouse sperm were performed to determine the integration of foreign DNA. The results showed that foreign DNA was successfully expressed in the treated mice. Furthermore, the expression and function of the foreign gene were analyzed in F₁ generation and F₂ generation mice at different levels, with the positive rates of foreign gene transfer into the F₁ and F₂ generations being 4.0 and 30.23 %, respectively. These results strongly support testicular injection as an effective method of producing transgenic animals and indicate that foreign genes can be stably passed on to the offspring. This research has theoretical and practical implications for the improvement in the quality of laboratory animals and for gene therapy.     

Detection of transgene in progeny at different developmental stages following testis-mediated gene transfer

We recently reported that exogenous DNA injected into testis as a liposome complex can be transferred into the egg via sperm by natural mating and integrated in the genome (testis-mediated gene transfer: TMGT). Here, we studied the efficiency of each of the several liposomes in associating foreign DNA with sperm, the expression of an introduced gene in early embryos, and the presence of the DNA in fetuses and pups at different ages. The CMV/beta-actin/EGFP fusion gene, encapsulated with different liposomes, was injected into rat testis, and spermatozoa in the cauda epididymis were obtained 1, 4, and 14 days after injection. We tested each of the 8 liposomes, and found that only 2, DMRIE-C and SuperFect, led to the detection of foreign DNA on all of the days examined, with relatively higher ratios of rats having positive sperm. By means of TMGT using either of those two liposomes, more than 80% of morula-stage embryos expressed EGFP, as observed by fluorescence microscopy. Then we detected introduced DNA in the progeny by PCR and Southern dot blot, and found that the ratio of animals carrying the foreign DNA decreased as they developed, and that only a part of postpartum progeny were foreign-DNA-positive with high incidence of mosaicism. These results suggest that, although, the success rate is still limited, foreign DNA could be integrated into the genome of the progeny by TMGT at least under specific experimental conditions, the efficiency of which depends largely on the characteristics of the liposome. The results also suggest that TMGT could be applicable to fetal gene therapy as well as to the generation of transgenic animals.     

小鼠睾丸注射不同转染试剂和注射方法对外源基因表达的影响

为探讨不同转染试剂(LipofectamineTM LTXPLUSTM、Lipofectamine2000和纳米化聚酰胺-胺型树枝状聚合物(PAMAM-D))和睾丸注射方法 (睾丸网注射、曲精细管注射和间质注射)对转基因小鼠生产效率的影响,将pEGFP-C1质粒分别与不同转染试剂混合后,按照不同的注射方法注入小鼠睾丸内,30 d后检测小鼠精子密度、活力、精子阳性率以及配种后仔鼠转基因阳性率。结果 3种转染试剂对小鼠繁殖性能影响由小到大依次为LipofectamineTM LTXPLUSTM、Lipofectamine 2000和PAMAM-D。转染后LipofectamineTM LTXPLUSTM、Lipofectamine 2000和PAMAM-D组精子的GFP阳性率分别为35.65%±0.69%、12.86%±0.35%和10.04%±0.20%。配种后仔鼠的PCR阳性率分别为29.17%、13.70%和5.88%。3种不同注射方法对小鼠睾丸都造成损伤,由小到大依次为睾丸网注射、曲精细管注射和睾丸间质注射,三者的阳性精子比例分别为35.13%±1.727%、15.13%±1.457%和0%,配种后仔鼠的PCR阳性率分别为33.3%、12.5%和0%。结果表明,LipofectamineTM LTXPLUSTM和睾丸网注射对小鼠睾丸的损伤最小,并能获得较高的转染效率。     

Transgenic mice aberrantly expressing human ornithine decarboxylase gene.

We have generated transgenic mice carrying human ornithine decarboxylase gene. Two different transgene constructs were used: (i) a 5'-truncated human ornithine decarboxylase gene and (ii) an intact human ornithine decarboxylase gene. Transgenic mice carrying the 5'-truncated gene did not express human ornithine decarboxylase-specific mRNA. Transgenic mice carrying the intact human ornithine decarboxylase gene expressed human-specific ornithine decarboxylase mRNA in all tissues studied. However, as indicated by actual enzyme assays, the expression pattern was highly unusual. In comparison with their wild-type littermates, the transgenic mice exhibited greatly elevated enzyme activity in almost every tissue studied. Ornithine decarboxylase activity was moderately elevated in parenchymal organs such as liver, kidney, and spleen. Tissues like heart, muscle, lung, thymus, testis, and brain displayed an enzyme activity that was 20 to 80 times higher than that in the respective tissues of nontransgenic animals. The offspring of the first transgenic male founder animal did not show any overt abnormalities, yet their reproductive performance was reduced. The second transgenic founder animal, showing similar aberrant expression of ornithine decarboxylase in all tissues studied, including an extremely high activity in testis, was found to be infertile. Histological examination of the tissues of the latter animal revealed marked changes in testicular morphology. The germinal epithelium was hypoplastic, and the spermatogenesis was virtually totally shut off. Similar examination of male members of the first transgenic mouse line revealed comparable, yet less severe, histological changes in testis.     

Effective generation of transgenic pigs and mice by linker based sperm-mediated gene transfer.

Background

Transgenic animals have become valuable tools for both research and applied purposes. The current method of gene transfer, microinjection, which is widely used in transgenic mouse production, has only had limited success in producing transgenic animals of larger or higher species. Here, we report a linker based sperm-mediated gene transfer method (LB-SMGT) that greatly improves the production efficiency of large transgenic animals.

Results

The linker protein, a monoclonal antibody (mAb C), is reactive to a surface antigen on sperm of all tested species including pig, mouse, chicken, cow, goat, sheep, and human. mAb C is a basic protein that binds to DNA through ionic interaction allowing exogenous DNA to be linked specifically to sperm. After fertilization of the egg, the DNA is shown to be successfully integrated into the genome of viable pig and mouse offspring with germ-line transfer to the F1 generation at a highly efficient rate: 37.5% of pigs and 33% of mice. The integration is demonstrated again by FISH analysis and F2 transmission in pigs. Furthermore, expression of the transgene is demonstrated in 61% (35/57) of transgenic pigs (F0 generation).

Conclusions

Our data suggests that LB-SMGT could be used to generate transgenic animals efficiently in many different species.     

Transferrin overexpression alters testicular function in aged mice

Many studies have shown a correlation between transferrin (Tf) concentration and sperm yield in several mammalian species. We have used transgenic mice expressing human Tf (hTf) to investigate if overexpression of Tf increases the efficiency of mouse spermatogenesis. We demonstrated that a 36% increase of Tf does not ameliorate the efficiency of mouse spermatogenesis but on the contrary resulted in a 36% decrease of testis sperm reserves. Tf overexpression had no effect on testicular determination and development, however testicular function of these transgenic mice was affected in an age-dependent manner. At 16 months of age, testicular and epididymal weights were significantly reduced. While spermatogenesis was qualitatively normal, testicular functions were perturbed. In fact, testosterone rate after human chorionic gonadotropin (hCG) stimulation was lower in Tf overexpressing mice. Intratesticular concentration of estradiol-17beta was increased and fluid accumulation after ligation of rete testis was more abundant in these transgenic mice. Surprisingly, we found that endogenous Tf levels were also increased in Tf overexpressing mice and we demonstrated for the first time that Tf may serve to upregulate its own expression in testis. Collectively, our data show that Tf overexpression has negative effects on testicular function and that Tf levels require strict regulation in the testis.     

Efficient and simple production of transgenic mice and rabbits using the new DMSO-sperm mediated exogenous DNA transfer method

A high efficient and simple transgenic technology on mice and rabbits to transfect spermatozoa with exogenous DNA/DMSO complex to obtain transgenic offspring, which is namely called DMSO-sperm mediated gene transfer (SMGT). Mouse sperm could be either directly transfected via injection into testis or cultured in vitro with the plasmed DNA containing the enhanced green fluorescent protein (EGFP) that could be expressed in the embryos and offspring. Then, 36 living transgenic rabbits were produced using the same technology, and the transgenic ratio of 56.3% was detected using PCR and Southern blot. As the controls, the transgenic ratios of 39.6% and 47.8% have also been tested using the liposomes mediated technology of Tfx-50 Reagent or Lipefectamin-2000, respectively. The results show that the female transgenic rabbits, as the mammary gland bioreactor models, could express the human tissue plasminogen activator mutant (htPAm) in their mammary cells when they are adult.