To construct a directional cDNA library from Chinese giant salamander Andrias davidianus liver by SMART(switching mechanism at 5′ end of RNA transcript)technique, we purified the mRNA from Andrias davidianus liver an...To construct a directional cDNA library from Chinese giant salamander Andrias davidianus liver by SMART(switching mechanism at 5′ end of RNA transcript)technique, we purified the mRNA from Andrias davidianus liver and the first strand cDNA was synthesized through reverse transcription by using a modified oligo(dT)primer(contained sfi ⅠB site). We used the SMART oligonucleotide (contained sfi ⅠA site) as a template so that the first strand cDNA could be extended over the 5′ end of mRNA. The double strand cDNA was amplified by LD PCR (long distance PCR) with the above two primers and then digested by sfi Ⅰ (ⅠA and ⅠB) restriction enzyme. After cDNA fractionation through CHROMA SPIN column, the double strand cDNA was ligated into the sfi Ⅰ digested λtripIEx2 vector and then the recombinant DNA was packaged in vitro . The content of the unamplified Andrias davidianus liver cDNA library is 1 5×10 6 in which the percentage of recombinant clones is about 98 9%. The titer of the amplified cDNA library is 1 0×10 10 pfu/ml and the average exogenous inserts of the recombinants is 1 25 kb. These results show that the Andrias davidianus liver cDNA library has excellent quality.展开更多
AIM:Transfer and expression of insulin gene in vivo are an alternative strategy to improve glycemic control in type 1 diabetes. Hydrodynamics-based procedure has been proved to be very efficient to transfer naked DNA ...AIM:Transfer and expression of insulin gene in vivo are an alternative strategy to improve glycemic control in type 1 diabetes. Hydrodynamics-based procedure has been proved to be very efficient to transfer naked DNA to mouse livers. The basal hepatic insulin production mediated by this rapid tail vein injection was studied to determine its effect on the resumption of glycemic control in type 1 diabetic mice.METHODS: Engineered insulin cDNA was inserted into plasmid vectors under a CMV promoter, and transferred into STZ induced diabetic mice by hydrodynamic procedure.Glucose levels, body weight of treated mice, insulin levels,immunohistology of the liver, and quantity of insulin mRNA in the liver were assayed to identify the improvement of hyperglycemic complication after plasmid administration.Sleeping Beauty, a transposon system, was also used to prolong the insulin expression in the liver.RESULTS: After plasmid administration, Plasma insulin was significantly increased in the diabetic mice and the livers were insulin-positive by immunostaining. At the same time the hyperglycemic complication was improved. The blood glucose levels of mice were reduced to normal. Glucose tolerance of the treated diabetic mice was improved. Body weight loss was also ameliorated. The rapid tail vein injection did not cause any fatal result.CONCLUSION: Our results suggested that insulin gene could be efficiently transferred into the livers of diabetic mice via rapid tail vein injection and it resulted in high level of insulin expression. The basal hepatic insulin production mediated by hydrodynamics-based administration improved the glycemic control in type 1 diabetes dramatically and ameliorated diabetic syndromes. Hydrodynamics-based administration offers a simple and efficient way in the study of gene therapy for type 1 diabetes.展开更多
文摘To construct a directional cDNA library from Chinese giant salamander Andrias davidianus liver by SMART(switching mechanism at 5′ end of RNA transcript)technique, we purified the mRNA from Andrias davidianus liver and the first strand cDNA was synthesized through reverse transcription by using a modified oligo(dT)primer(contained sfi ⅠB site). We used the SMART oligonucleotide (contained sfi ⅠA site) as a template so that the first strand cDNA could be extended over the 5′ end of mRNA. The double strand cDNA was amplified by LD PCR (long distance PCR) with the above two primers and then digested by sfi Ⅰ (ⅠA and ⅠB) restriction enzyme. After cDNA fractionation through CHROMA SPIN column, the double strand cDNA was ligated into the sfi Ⅰ digested λtripIEx2 vector and then the recombinant DNA was packaged in vitro . The content of the unamplified Andrias davidianus liver cDNA library is 1 5×10 6 in which the percentage of recombinant clones is about 98 9%. The titer of the amplified cDNA library is 1 0×10 10 pfu/ml and the average exogenous inserts of the recombinants is 1 25 kb. These results show that the Andrias davidianus liver cDNA library has excellent quality.
文摘AIM:Transfer and expression of insulin gene in vivo are an alternative strategy to improve glycemic control in type 1 diabetes. Hydrodynamics-based procedure has been proved to be very efficient to transfer naked DNA to mouse livers. The basal hepatic insulin production mediated by this rapid tail vein injection was studied to determine its effect on the resumption of glycemic control in type 1 diabetic mice.METHODS: Engineered insulin cDNA was inserted into plasmid vectors under a CMV promoter, and transferred into STZ induced diabetic mice by hydrodynamic procedure.Glucose levels, body weight of treated mice, insulin levels,immunohistology of the liver, and quantity of insulin mRNA in the liver were assayed to identify the improvement of hyperglycemic complication after plasmid administration.Sleeping Beauty, a transposon system, was also used to prolong the insulin expression in the liver.RESULTS: After plasmid administration, Plasma insulin was significantly increased in the diabetic mice and the livers were insulin-positive by immunostaining. At the same time the hyperglycemic complication was improved. The blood glucose levels of mice were reduced to normal. Glucose tolerance of the treated diabetic mice was improved. Body weight loss was also ameliorated. The rapid tail vein injection did not cause any fatal result.CONCLUSION: Our results suggested that insulin gene could be efficiently transferred into the livers of diabetic mice via rapid tail vein injection and it resulted in high level of insulin expression. The basal hepatic insulin production mediated by hydrodynamics-based administration improved the glycemic control in type 1 diabetes dramatically and ameliorated diabetic syndromes. Hydrodynamics-based administration offers a simple and efficient way in the study of gene therapy for type 1 diabetes.
