Production of germline transgenic pigs co-expressing double fluorescent proteins by lentiviral vector

Anti-tembusu virus of capsid-targeted viral inactivation delivered by lentiviral vector in vivo

Tembusu virus (TMUV) is a member of genus flavivirus, which mainly causes decrease in production in egg ducks and neurological symptom in meatducks, causing serious economic losses to the poultry industry. Recently, the commercialized TMUV vaccines are mainly the WF100 live vaccine and the attenuated live vaccine (FX2010-180P), so it is particularly important to find new methods to combat TMUV. The capsid-targeted viral inactivation (CTVI) strategy is based on a viral core protein and an exogenous factor that can destroy viral DNA or RNA. Lentivirus vectors are an effective tool for transferring the recombinant lentiviruses to target cells and are a promising system for efficient gene delivery. This study injected recombinant lentivirus carrying the Cap-SNase and Cap-Linker-SNase fusion proteins into duck early embryos at 109 TU/mL, achieving widespread expression of the fusion proteins in duck embryo tissues. After TMUV infection, the symptoms of the ducks in the Cap-SNase and Cap-Linker-SNase groups were significantly alleviated to the 1640 group. Pathological sections showed that compared with the 1640 group, the pathological damage in the Cap-SNase and Cap-Linker-SNase groups was greatly alleviated, and the virus loads in the feces, blood and tissues of Cap-SNase or Cap-Linker-SNase groups were significantly lower than those in the 1640 group. The results indicate that the Cap-SNase or Cap-Linker-SNase fusion proteins delivered by lentivirus have anti-TMUV effect. This study combines lentiviral vectors with CTVI strategy for the first time, which could be a simple and practical technology to treating human or animal diseases or biomedical animals.

[Preparation of GH/tPA double transgenic mice and gene expression analysis]

OBJECTIVE

To obtain GH/tPA double transgenic mice, analyze the expression level of tissue plasminogen activator (tPA) in the mammary glands and observe the growth and development of the transgenic mice.

METHODS

We obtained the offspring mice of 2 tPA single transgenic mice (P03 and P05) mated with a female nontransgenic mouse by microinjection of linearized GH plasmid into the fertilized eggs and embryo transfer. PCR was used to detect the gene integration. The expression levels of tPA in single gene and double gene transgenic mice were compared using ELISA and Western blotting. We assessed the effects of GH gene transduction on the growth and development of the transgenic mice by observing body weight changes of the mice at each developmental stage.

RESULTS

A total of 286 fertilized eggs were collected from P03 mice, and after embryo transfer, 77 offspring mice were obtained, including 16 tPA single transgenic mice (7 male, 9 female) and 13 GH/tPA double transgenic mice (8 male, 5 female) as confirmed by PCR. The integration rate of the double genes was 16.9%. A total of 175 fertilized eggs were collected from P05 mice, and 34 offspring mice were obtained including 12 tPA single transgenic mice (5 male, 7 female) and 7 GH/tPA double transgenic mice (3 male, 4 female), in which the integration rate of the double genes was 20.6%. The highest expression level of tPA in the mammary gland was significantly higher in double than in single transgenic mice (674 μg/mL vs 82.5 μg/mL, P < 0.05). In the whole growth cycle of the mice, no significant difference in weight gain was observed in the single or double transgenic mice as compared with the na?ve mice (P>0.05).

CONCLUSION

We successfully prepared GH/tPA double transgenic mice, in which GH gene transduction significantly increases the expression level of target gene tPA without affecting the growth and development of the transgenic mice. This success suggests a promising approach to preparing transgenic animals for producing pharmaceutical proteins and the breeding of the transgenic animals.

An Event-Specific Real-Time PCR Method for Measuring Transgenic Lysozyme Goat Content in Trace Samples

Lysozymes are used in sterilisation, antisepsis, dairy additives, inflammation, and cancer. One transgenic goat line expressing high levels of human lysozyme (hLZ) in goat milk has been developed in China. Herein, we established an event-specific real-time polymerase chain reaction (real-time PCR) method to detect the transgenic hLZ goat line. The developed method has high specificity, sensitivity and accuracy, and a wide quantitative dynamic range. The limit of detection and limit of quantification was 5 and 10 copies per reaction, respectively. The practical sample analysis results showed that the method could identify and quantify transgenic lysozyme content in trace samples in routine lab analyses. Furthermore, the potential applicability in risk assessment, such as molecular characterisation and gene horizontal transfer, was confirmed. We believe that this method is suitable for the detection of transgenic hLZ goat line and its derivate.

Assisted Reproductive Techniques and Genetic Manipulation in the Common Marmoset

Genetic modification of nonhuman primate (NHP) zygotes is a useful method for the development of NHP models of human diseases. This review summarizes the recent advances in the development of assisted reproductive and genetic manipulation techniques in NHP, providing the basis for the generation of genetically modified NHP disease models. In this study, we review assisted reproductive techniques, including ovarian stimulation, in vitro maturation of oocytes, in vitro fertilization, embryo culture, embryo transfer, and intracytoplasmic sperm injection protocols in marmosets. Furthermore, we review genetic manipulation techniques, including transgenic strategies, target gene knock-out and knock-in using gene editing protocols, and newly developed gene-editing approaches that may potentially impact the production of genetically manipulated NHP models. We further discuss the progress of assisted reproductive and genetic manipulation techniques in NHP; future prospects on genetically modified NHP models for biomedical research are also highlighted.

The 18 kDa Translocator Protein (TSPO) Overexpression in Hippocampal Dentate Gyrus Elicits Anxiolytic-Like Effects in a Mouse Model of Post-traumatic Stress Disorder

The translocator protein (18 kDa) (TSPO) recently attracted increasing attention in the pathogenesis of post-traumatic stress disorder (PTSD). This study is testing the hypothesis that the overexpression of TSPO in hippocampus dentate gyrus (DG) could alleviate the anxiogenic-like response in the mice model of PTSD induced by foot-shock. In this study, hippocampal DG overexpression of TSPO significantly reversed the increase of the contextual freezing response, the decrease of the percentage of both entries into and time spent in the open arms in elevated plus maze test and the decrease of the account of crossings from the dark to light compartments in light–dark transition test induced by electric foot-shocks procedure. It was further showed that the behavioral effects of TSPO overexpression were blocked by PK11195, a selective TSPO antagonist. In addition, the expression of TSPO and level of allopregnanolone (Allo) decreased in the mouse model of PTSD, which was blocked by overexpression of TSPO in hippocampal dentate gyrus. The difference of neurogenesis among groups was consistent with the changes of TSPO and Allo, as evidenced by bromodeoxyuridine (BrdU)- positive cells in the hippocampal dentate gyrus. These results firstly suggested that TSPO in hippocampal dentate gyrus could exert a great effect on the occurrence and recovery of PTSD in this animal model, and the anti-PTSD-like effect of hippocampal TSPO over-expression could be at least partially mediated by up-regulation of Allo and subsequent stimulation of the adult hippocampal neurogenesis.