【目的】利用CRISPR/Cas9技术建立绵羊示踪脐带间充质干细胞系,为间充质干细胞的临床治疗与分化机制研究奠定基础。【方法】根据绵羊ROSA26的基因组序列,利用在线工具ZiFiT Targeter Version 4.2设计合成3对引物,利用点突变法,以px330...【目的】利用CRISPR/Cas9技术建立绵羊示踪脐带间充质干细胞系,为间充质干细胞的临床治疗与分化机制研究奠定基础。【方法】根据绵羊ROSA26的基因组序列,利用在线工具ZiFiT Targeter Version 4.2设计合成3对引物,利用点突变法,以px330质粒为模板分别进行PCR,DpnⅠ去除质粒DNA后,PCR产物自身环化,酶切测序鉴定,构建以绵羊Rosa26为靶标基因的sgRNA/Cas9载体,构建的质粒含Cas9和向导RNA(single-guide RNA,sgRNA)表达盒,由U6启动子驱动表达。将上述载体分别利用脂质体转染绵羊脐带间充质干细胞(sUMSCs),提取其基因组PCR后进行T7E1酶切,琼脂糖电泳分析条带灰度以检测载体编辑活性。根据sgRNA序列在绵羊ROSA26靶位点的上下游设计并合成左、右同源臂扩增引物,提取绵羊全基因组为模板分别进行PCR扩增得到左右同源臂,回收纯化后分别与pMD19-Simple连接,酶切测序鉴定获得左、右同源臂重组质粒。根据PCR引入的酶切位点,将左同源臂质粒和Donor表达载体DC-DON-SH02ROSA26进行酶切连接,鉴定获得左臂重组打靶载体,使用相同方法将右同源臂质粒连接到左臂打靶载体上,鉴定获得Donor打靶载体,载体携带嘌呤霉素抗性基因和绿色荧光蛋白(GFP)报告基因。在生长良好的sUMSCs中加入不同浓度的嘌呤霉素,观察细胞存活时间,确定最佳抗性筛选浓度和时间。利用脂质体共转sgRNA/Cas9载体和Donor载体到绵羊间充质干细胞,在其ROSA26位点切割DNA双链,在DNA断裂处通过同源重组方式引入报告基因,转染48 h后进行嘌呤霉素抗性筛选,筛选结束后更换正常培养基继续培养,观察绿色荧光的表达并提取阳性细胞基因组,针对ROSA26位点设计上下游两对引物对其进行PCR检测其整合情况。【结果】(1)针对绵羊Rosa26位点设计3对PCR引物,利用点突变法将sgRNA克隆至px330的BbsⅠ酶切位点上,成功构建sgRNA/Cas9载体px330-sgRNA1/2/3,将其分别转染sUMSCs,T7E1酶切结果表明px330-sgRNA2/3出现脱靶现象,未在靶位点发生编辑,px330-sgRNA1的编辑效率最高,约为20%;(2)基于sgRNA1,PCR法获得打靶载体的左、右同源臂,经一系列分子生物学方法先后连接到载体DC-DON-SH02ROSA26上,经酶切和PCR鉴定,成功获得绵羊ROSA26位点的重组载体sROSA26-HA;(3)筛选得到sUMSCs最佳抗性浓度时间,利用Lipofectamine2000共转染sgRNA/Cas9载体和Donor重组载体到sUMSCs,1.5μg·mL^-1嘌呤霉素筛选15d至对照组细胞全部死亡,获得的阳性克隆并扩大培养。显微镜下可观察到明显的绿色荧光,且与对照组相比,阳性细胞克隆的基因组PCR均检测到特异条带,表明sUMSCs的ROSA26位点发生同源重组,GFP基因被成功敲入到基因组中并能正常表达,该细胞可以用于动物疾病模型中追踪sUMSCs的去向和分化方向的研究。【结论】成功利用CRISPR/Cas9系统在sUMSCs内实现外源GFP基因的定点敲入,获得绵羊示踪脐带间充质干细胞系,为间充质干细胞进一步的临床转化奠定了基础。展开更多
Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a larg...Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a large number of reporter mouse models have been generated. Reporter mouse models provide systems that enable the studies of live cell imaging, cell lineage tracing, immunological research and cancers etc. in vivo. In this review, we describe the types of different reporter genes and reporter mouse models including, random reporter strains, Cre reporter strains and ROSA26 reporter strains. Collectively, these reporter mouse models have broadened scientific inquires and provided potential strategies for generation of novel reporter animal models with enhanced capabilities.展开更多
AIM To stably correct tyrosinaemia in proliferating livers of fumarylacetoacetate-hydrolase knockout(Fah-/-) mice by homologous-recombination-mediated targeted addition of the Fah gene.METHODS C57 BL/6 Fah?exon5 mice ...AIM To stably correct tyrosinaemia in proliferating livers of fumarylacetoacetate-hydrolase knockout(Fah-/-) mice by homologous-recombination-mediated targeted addition of the Fah gene.METHODS C57 BL/6 Fah?exon5 mice served as an animal model for human tyrosinaemia type 1 in our study. The vector was created by amplifying human Fah c DNA including the TTR promoter from a lentivirus plasmid as described. The Fah expression cassette was flanked by homologous arms(620 bp and 749 bp long) of the Rosa26 gene locus. Mice were injected with 2.1 × 108 VP of this vector(r AAV8-ROSA26.HAL-TTR.FahROSA26.HAR) via the tail vein. Mice in the control group were injected with 2.1 × 108 VP of a similar vector but missing the homologous arms(r AAV8-TTR.Fah). Primary hepatocytes from Fah-/-recipient mice, treated with our vectors, were isolated and 1 × 106 hepatocytes were transplanted into secondary Fah-/-recipient mice by injection into the spleen. Upon either vector application or hepatocyte transplantation NTBC treatment was stopped in recipient mice. RESULTS Here, we report successful HR-mediated genome editing by integration of a Fah gene expression cassette into the "safe harbour locus" Rosa26 by recombinant AAV8. Both groups of mice showed long-term survival, weight gain and FAH positive clusters as determined by immunohistochemistry analysis of liver sections in the absence of NTBC treatment. In the group of C57 BL/6 Fah?exon5 mice, which have been transplanted with hepatocytes from a mouse injected with r AAV8-ROSA26.HAL-TTR.Fah-ROSA26.HAR 156 d before, 6 out of 6 mice showed long-term survival, weight gain and FAH positive clusters without need for NTBC treatment. In contrast only 1 out 5 mice, who received hepatocytes from r AAV8-TTR.Fah treated mice, survived and showed few and smaller FAH positive clusters. These results demonstrate that homologous recombinationmediated Fah gene transfer corrects the phenotype in a mouse model of human tyrosinaemia type 1(Fah-/-mice) and is long lasting in a proliferating state of the liver as shown by withdrawal of NTBC treatment and serial transplantation of isolated hepatocytes from primary Fah-/-recipient mice into secondary Fah-/-recipient mice. This long term therapeutic efficacy is clearly superior to our control mice treated with episomal r AAV8 gene therapy approach.CONCLUSION HR-mediated r AAV8 gene therapy provides targeted transgene integration and phenotypic correction in Fah-/-mice with superior long-term efficacy compared to episomal r AAV8 therapy in proliferating livers.展开更多
Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational modifications.However,toxic proteins and membrane proteins are often ...Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational modifications.However,toxic proteins and membrane proteins are often difficult-to-express in living cells.Alternatively,cell-free protein synthesis can be employed.This study explores innovative strategies for enhancing the production of challenging proteins through the modification of CHO cells by investigating both,cell-based and cell-free approaches.A major result in our study involves the integration of a mutant eIF2 translation initiation factor and T7 RNA polymerase into CHO cell lysates for cell-free protein synthesis.This resulted in elevated yields,while eliminating the necessity for exogenous additions during cell-free production,thereby substantially enhancing efficiency.Additionally,we explore the potential of the Rosa26 genomic site for the integration of T7 RNA polymerase and cell-based tetracycline-controlled protein expression.These findings provide promising advancements in bioproduction technologies,offering flexibility to switch between cell-free and cell-based protein production as needed.展开更多
基金Shanghai Municipal Health and Family Planning Commission Scientific Research Project,Grant/Award Number:20154Y0075Shanghai Municipal Fund for Science and Technology Development,Grant/Award Number:15140904000+1 种基金Shanghai Public Health Clinical Center,Grant/Award Number:KY-GW-2017-04,KY-GW-2018-48National Natural Science Foundation of China,Grant/Award Number:31270217,31601908,81471397
文摘Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a large number of reporter mouse models have been generated. Reporter mouse models provide systems that enable the studies of live cell imaging, cell lineage tracing, immunological research and cancers etc. in vivo. In this review, we describe the types of different reporter genes and reporter mouse models including, random reporter strains, Cre reporter strains and ROSA26 reporter strains. Collectively, these reporter mouse models have broadened scientific inquires and provided potential strategies for generation of novel reporter animal models with enhanced capabilities.
基金Rebirth, SFB 738the "Deutsche Forschungsgemeinschaft" (Gerok-Grant) for financial support
文摘AIM To stably correct tyrosinaemia in proliferating livers of fumarylacetoacetate-hydrolase knockout(Fah-/-) mice by homologous-recombination-mediated targeted addition of the Fah gene.METHODS C57 BL/6 Fah?exon5 mice served as an animal model for human tyrosinaemia type 1 in our study. The vector was created by amplifying human Fah c DNA including the TTR promoter from a lentivirus plasmid as described. The Fah expression cassette was flanked by homologous arms(620 bp and 749 bp long) of the Rosa26 gene locus. Mice were injected with 2.1 × 108 VP of this vector(r AAV8-ROSA26.HAL-TTR.FahROSA26.HAR) via the tail vein. Mice in the control group were injected with 2.1 × 108 VP of a similar vector but missing the homologous arms(r AAV8-TTR.Fah). Primary hepatocytes from Fah-/-recipient mice, treated with our vectors, were isolated and 1 × 106 hepatocytes were transplanted into secondary Fah-/-recipient mice by injection into the spleen. Upon either vector application or hepatocyte transplantation NTBC treatment was stopped in recipient mice. RESULTS Here, we report successful HR-mediated genome editing by integration of a Fah gene expression cassette into the "safe harbour locus" Rosa26 by recombinant AAV8. Both groups of mice showed long-term survival, weight gain and FAH positive clusters as determined by immunohistochemistry analysis of liver sections in the absence of NTBC treatment. In the group of C57 BL/6 Fah?exon5 mice, which have been transplanted with hepatocytes from a mouse injected with r AAV8-ROSA26.HAL-TTR.Fah-ROSA26.HAR 156 d before, 6 out of 6 mice showed long-term survival, weight gain and FAH positive clusters without need for NTBC treatment. In contrast only 1 out 5 mice, who received hepatocytes from r AAV8-TTR.Fah treated mice, survived and showed few and smaller FAH positive clusters. These results demonstrate that homologous recombinationmediated Fah gene transfer corrects the phenotype in a mouse model of human tyrosinaemia type 1(Fah-/-mice) and is long lasting in a proliferating state of the liver as shown by withdrawal of NTBC treatment and serial transplantation of isolated hepatocytes from primary Fah-/-recipient mice into secondary Fah-/-recipient mice. This long term therapeutic efficacy is clearly superior to our control mice treated with episomal r AAV8 gene therapy approach.CONCLUSION HR-mediated r AAV8 gene therapy provides targeted transgene integration and phenotypic correction in Fah-/-mice with superior long-term efficacy compared to episomal r AAV8 therapy in proliferating livers.
基金supported by the European Regional Development Fund(EFRE)and the German Ministry of Education and Research(BMBF 031B0831C).
文摘Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational modifications.However,toxic proteins and membrane proteins are often difficult-to-express in living cells.Alternatively,cell-free protein synthesis can be employed.This study explores innovative strategies for enhancing the production of challenging proteins through the modification of CHO cells by investigating both,cell-based and cell-free approaches.A major result in our study involves the integration of a mutant eIF2 translation initiation factor and T7 RNA polymerase into CHO cell lysates for cell-free protein synthesis.This resulted in elevated yields,while eliminating the necessity for exogenous additions during cell-free production,thereby substantially enhancing efficiency.Additionally,we explore the potential of the Rosa26 genomic site for the integration of T7 RNA polymerase and cell-based tetracycline-controlled protein expression.These findings provide promising advancements in bioproduction technologies,offering flexibility to switch between cell-free and cell-based protein production as needed.
