Construction of aquaporin 9 gene knockout mice using CRISPR/Cas9 gene editing system / 解剖学报

Objective To construct homozygous aquaporin 9(AQP-9)

Identification and survival analysis of TTA/TETO-CCKR-2 double transgenic mice / 中国组织工程研究

BACKGROUND: The inducible forebrain-specific cholecystokinin receptor-2 (CCKR-2) double transgenic (tTA/tetO-CCKR-2 tg, abbreviated as dtg) mice are an ideal model of anxiety-related diseases. However, there is still a lack of model identification and life related data OBJECTIVE: To identify the genomic DNA of the offspring and the specific expression of CCKR-2 transgene in the forebrain, and to analyze the survival probability of dtg mice. METHODS: α-CaMKII/tTA single transgenic mice and tetO-CCKR-2 single transgenic mice were cross-fertilized to construct a dtg mouse model. The genomic DNA was extracted from the tail of the offspring, and the genotypes were detected by PCR and agarose gel electrophoresis. Wild-type (WT) mice were used as controls. In situ hybridization was used to detect the expression of CCKR-2. Survival of dtg mice and WT mice (30 females and 30 males) was observed and recorded within 2 years. The study protocol was approved by the Experimental Animal Ethics Committee of Southwest Medical University, with an approval No. 20150068. RESULTS AND CONCLUSION: Agarose gel electrophoresis results showed the molecular weight of the PCR products of dtg mice was consistent with the expected target gene fragment. In situ hybridization results showed a strong signal of CCKR-2 was detected in the forebrain of dtg mice, but hardly present in the WT mice. The median survival time of dtg mice was 76 weeks in females and 77 weeks in males. The survival probability was decreased with age in dtg mice. The survival probability of WT mice was significantly better than that of dtg mice (P < 0.001). There was no significant sex difference between males and females of dtg mice (P=0.577). Therefore, the specific expression of CCKR-2 transgene in the forebrain can be identified using PCR amplification, genomic DNA extraction, agarose gel electrophoresis, and in situ hybridization. tTA/tetO-CCKR-2 double transgenic induction may shorten the survival time of mice, but no significant difference is observed between the females and males of dtg mice.

Breeding and genotype identification of Arrb2 gene knockout mice / 中国药理学通报

Aim To explore the optimal way of breeding and genotype identification of Arrb2 knockout mice, and to find a simple and quick polymerase chain reaction ( PCR) method for the genotyping of Arrb2 knockout mice. Methods Breeding homozygote genotype of Arrb2 gene knockout mice were copula-ted with wild-type C57BL/6J mice, and then the heterozygous mating were used for mating. The growth and development of off-spring were observed. The genomic DNA was extracted from the tail of two-week-old mice. PCR was employed to amplify the Arrb2 gene fragment, and electrophoresis was used to present the gene type. Results The breeding and reproducing were successful and three genotype offspring, including wild-type,heterozygous and homozygous knockout mice were obtained. Agarose gel electrophoresis results showed the size of PCR prod-ucts was about 186 bp and 224 bp, which was consistent with the expected target gene fragment, and identified Arrb2 gene knockout mice of different genotypes successfully. Western blot analysis demonstrated the lack ofβ-arrestin2 protein in the major organs from Arrb2 -/ - mice compared with Arrb2 +/ + and Arrb2 +/ - mice. Conclusions It is feasible to obtain the homo-zygous Arrb2 knockout mice by inbreeding heterozygotes. It is simple, rapid and reliable to identify mouse genetype by PCR.

Identification of the method of establishment of a DKO mouse model of Duchenne muscular dystrophy and regeneration of dystrophin expression in vivo after stem cell transplantation / 中国实验动物学报

Objective To establish a method of identification of DKO mouse model of Duchenne muscular dystro-phy, and to assess the dystrophin regeneration after stem cell transplantation.Methods Heterozygous mice were mated and the resulting offspring were used to identify their genotype by SSP-PCR.The plasma creatine kinase level was measured by biochemical analyzer and histological changes in the DKO mice were analyzed using HE staining.Human umbilical cord mesenchymal stem cells were prepared and injected into the DKO mice hindlimb muscle, and dystrophin expression was de-tected by immunofluorescence staining at 2 months after injection.Results Mating of heterozygous mice generated three kinds of genotype offsprings, and 21.2%of the offsprings were identified as DKO genotype (285 bp) .DKO mice showed dystrophic symptoms, their plasma creatine kinase level was as high as 16988.52 ±617.48 IU/L, and significant histologi-cal changes including diverse myocyte sizes, numerous centrally nucleated cells and connective tissue proliferation or in-flammatory cells infiltration.Human dystrophin expression was detected in the DKO mouse hindlimb muscle at two months after injection of human umbilical cord mesenchymal stem cells.Conclusion DKO mouse genotype can be identified by SSP-PCR, and DKO mouse is an ideal animal model for studies of stem cell therapy for Duchenne muscular dystrophy.

Comparison of three methods for total DNA extraction from mouse models / 中国比较医学杂志

Objective To establish a simple , fast and economic total DNA extraction method to serve the rapid identification of model mouse genotype in large number of mice .Methods Three methods, i.e.phenol extraction, isopropyl alcohol precipitation and mouse ear boiling methods were used to extract the total DNA from ten C 57-rasmodel mice.The purity and yield of DNA obtained by the three methods were compared , and polymerase chain reaction ( PCR) assay was used to compare the efficacy of the three extraction methods .Results Among the three methods , phenol extraction was the best and isopropyl alcohol precipitation was the poorest in DNA yield .In terms of DNA purity , the phenol extraction was the best and the mouse ear boiling method was the poorest .All the three methods could be used to extract the total DNA from mice serving as template of PCR reaction for the mouse genotype identification .The time consumption of three methods are 12.5 hr ,13 hr and 0.18 hr.Mouse ear boiling method was significantly lower than that of the other two methods ( P <0.01 ) ,.The obtained total DNA can be stored at conventional -20℃for 7 days and 30 days later still can be used as a template for PCR reaction .Conclusions Among the three methods studied , the mouse ear boiling method is simple and with the lowest cost , so it is feasible for total DNA extraction in scaled genotyping experiments .