Study On The Transgenic Mice Model Of Expression Mx Protein

Animal transgenic research is basically characterized by inserting the foreign gene into animal or changing the genetic composition of animal and passing on generation to generation stabily. Transgenic animal model is a high-level research system and the great tool of studying on gene function, pathogenesis, drug screening and clinical medicine.Mx proteins are members of the dynamin superfamily of large GTPases induced by interferon (IFN). The studies found that the Mx proteins of many animals can inhibit the replication of a wide range of RNA viruses, including the high pathogenic avian influenza virus (AIV), Thogoto virus (THVO) and vesicular stomatitis virus (VSV). To gain transgenic mice model which could express Mx protein and resist to influenza virus, we inserted the Mx gene of resistance to influenza virus into ICR mice, providing the basis for gene function research.In this stusy, the amplicated chicken Mx gene was ligated into pcDNA3.1 and prokaryotic expression vector pProExHTa, the identified positive recombinant plasmid was transformed into E.coli BL21, and induced to express by IPTG. The New Zealand white rabbits were immunized with fusional Mx protein purified by cutting the corresponding SDS-PAGE gel. the 293T cells were transfected by pcDNA3.1-Mx and analysised with indirect immunofluorescent assay. The result indicated that the recombination plasmid pProExHTa-Mx constructed successfully and expressed the corresponding protein stably after induced with IPTG, the relative molecular mass of the expression product was about 80 kDa, identical with the predicted value. Western blot and indirect immunofluorescent assay showed the antiserum had good immune response with Mx protein which has similar biologic activity.Transgenic mice were mated with wild type mice based on having positive F1 Mx transgenic mice, the offspring were detected by PCR and Southern blot in DNA level. 29 F2 Mx transgenic mice were obtained. Mx mRNA was found to be expressed in heart, liver, spleen, lung, kidney brain and muscle of the transgenic mouse by RT-PCR. The indirect immunofluorescent assay indicated that the Mx protein expressed in lung and liver. With the same method, 44 F3 and 19 F4 Mx transgenic mice were gained. The results indicated that the transgenic mice model in which Mx gene can be stably and inherited expressed has been established.To evaluated the anti-avian influenza virus effect of the Mx transgenic mice in vivo, the 13 F3 Mx transgenic mice were infected with 200LD50 H5N1 avian influenza virus, the wide type ICR mice used as control group. the result was analysised by the clinical symptom, the viral content in lung, weight change, pathological changes and survival rate. The symptom and pathological changes of Mx transgenic mice was mild, the viral content in lung of the Mx transgenic mice was lower than the wild type mice, there had three Mx transgenic mice to survive, the survival rate is 30%. however, the control group mice died completely. The result showed that Mx transgenic mice can resist avain influenza virus markedly.In this sduty, we gained Mx transgenic mice model which expressed Mx protein stably. The triansgenic mice could be valuable for testing antivirus effort of Mx protein. In transgenic mice individual level, we proved that the chicken Mx protein had resistant effect against avian influenza virus, that provide the basis for the Mx transgenic chicken preparation and the disease-resistant breeding.