红色荧光蛋白和荧光素酶双报告基因转基因小鼠的建立

背景与目的:活体动物体内光学成像(optical in vivo imaging)主要采用生物发光与荧光两种技术。生物发光是用荧光素酶(luciferase,Luc)基因标记细胞或DNA,而荧光技术则采用荧光报告基团(GFP、RFP、Cyt及dyes等)进行标记,利用一套非常灵敏的光学检测仪器,能够直接监控活体生物体内的细胞活动和基因行为,生物发光成像具有高的灵敏度和特异性,同时生物发光信号可用于精确定量,而荧光成像具有方便、便宜、直观、标记靶点多样和易于被大多数研究人员接受的优点。本研究基于慢病毒介导的转基因方法制备红色荧光蛋白(red fluorescent protein,RFP)和Luc双报告基因转基因小鼠(即RL转基因小鼠),将这两种技术融为一体。方法:制备携带RFP和Luc基因(简写RL基因)的慢病毒,然后将携带RL基因的慢病毒注入小鼠单细胞受精卵卵周隙以感染受精卵,胚胎移植进假孕母鼠以获得仔鼠,应用小动物活体成像仪、体视荧光显微镜和PCR等在蛋白和DNA水平上筛选和鉴定,并获得RL转基因小鼠。结果:移植卵周隙注射有慢病毒的胚胎125枚给6只假孕母鼠,其中4只假孕母鼠怀孕,共生仔鼠20只;利用小动物活体成像仪检测RFP和Luc表达,在蛋白水平证实20只F0代中,3只高表达RFP和Luc;DNA水平检测证实,3只RFP和Luc阳性的小鼠基因组中确实整合有外源转基因RL,预示基因型鉴定结果很好验证了小动物活体成像仪筛选和鉴定结果。此外,RL转基因首建鼠基因组中整合的RL转基因可稳定遗传至下一代,并能正常表达。RL转基因小鼠主要脏器均可见红色荧光和Luc信号,但不同脏器间荧光和Luc强度有差异。结论:成功制备RL双报告基因转基因小鼠,为后续研究干细胞在肿瘤发生、发展和转移中的作用和造血重构等提供双报告基因标记的各种移植用供体细胞,并对此供体细胞及其在体内衍生的细胞进行灵敏的非损伤、实时可视化体内跟踪。

Generation of RFP and luciferase double transgenic mice

Background and purpose:Optical in vivo imaging includes bioluminescence and fluorescence technology.Bioluminescence technique is that cells or DNA are labeled by gene luciferase(Luc),while fluorescence technique is marked by a fluorescent reporter(GFP and RFP,Cyt,and dyes,etc.),then using a very sensitive optical detection equipment to directly monitor the activity and gene behavior of the cells of living organisms in vivo.Bioluminescence imaging has high sensitivity and specificity compared with fluorescence imaging,moreover,bioluminescence signal can be used for precise quantitative while fluorescence imaging has the advantages of convenient,inexpensive,intuitive,and marking targets diversely and easily accepted by the majority of researchers.The study was aimed to generate red fluorescent protein(RFP) and Luc double transgenic mice(i.e.,RL transgenic mice) by lentivirus-mediated delivery of foreign genes into zygotes.Methods:RL transgenic mice were generated by the subzonal injection of lentivirus harboring RFP and Luc gene into single-cell fertilized eggs of mice to infect fertilized eggs,and subsequently embryos infected by lentivirus were transplanted into the pseudopregnant mice to attain F0 mice,followed by screening RL transgenic mice from potential founders via RFP and Luc assay by using the Xenogen IVIS Lumina Imaging System at birth,and subsequently confirmed the results of RFP and Luc assay by PCR-based genotyping.Results:In our study,125 virus-injected eggs were transplanted into 6 pseudopregnant mice to attain 20 potential transgenic founders.Three RFP-and Luc-positive mice were found via RFP and Luc assay by using the Xenogen IVIS Lumina Imaging System 2 days after birth.PCR-based genotyping indicated that RL gene actually integrated into the genome of three RL-positive F0 mice,which confirmed the results of RFP and Luc assay.Furthermore,RL transgene could be transmitted from founders to subsequent generation(F1 progeny).Red fluorescence and Luc could be detected in different adult organs including testis,kidney,stomach,intestine,lung,liver,brain,thymus,spleen and heart under stereo fluorescence microscope and/or by the Xenogen IVIS Lumina Imaging System.Conclusion:RFP and Luc double transgenic mice were successfully produced to provide a variety of dual-reporter gene markers with donor cell transplantation for follow-up study of cancer stem cells in tumor development,metastasis and hematopoietic reconstruction,and traced this donor-derived cells and cells in the body with non-sensitive damage,real-time visualization in vivo.