The Study On The Envelope Proteins Of Jaagsiekte Sheep Retrovirus Cause The Cell Transformation In Vitro And In Vivo

Ovine pulmonary adenocarcinoma (OPA) was caused by exogenous Jaagsiekte sheep retrovirus (exJSRV), induced chronic, contact, infectious and neoplastic diseases. The pathological features of OPA are similar to human bronchial lung cancer, so OPA is an ideal animal model for the study of human small bronchial lung cancer. Exogenous Jaagsiekte sheep retrovirus (exJSRV) is the only known virus which can cause adenocarcinoma of lung naturally. JSRV is similar to that of the other retroviruses in the structure of the gene organization:gag, pro, pol and env; The envelope gene encodes viral envelope protein and exists on the surface of virus particles, mainly responsible for the specific binding for virion and the target cells, then induces the membrane fusion to make virus particles enter into the target cells. Exogenous JSRV envelope protein is important on the induction of the cell transformation, and mice can be used as a good model for the study on the function of exogenous JSRV envelope protein.For further study on the function of exogenous Jaagsiekte sheep retrovirus envelope protein, this experiment built the exISRV-env recombinant plasmid pcDNA3.1(+)/exJSRV-env, exogenous Jaagsiekte sheep retrovirus envelope genes were came from the sheep lung tissue of Inner Mongolia naturally infected sheep pulmonary adenoma, identification by PCR, enzyme digestion and nucleic acid sequencing methods. The recombinant plasmids pcDNA3.1(+)/exJSRV-env were transiently transfected into NIH3T3 cells by Lipofectamine LTX. After the transfection of the recombinant plasmid, observed whether caused the cell transformation; The transfected cells were inoculated subcutaneously into nude mice to observe whether caused tumorigenicity. The in vivo transfection reagent mixed with recombinant plasmid, then injected into the BALB/c mice through tail vein; By H.E staining observed if the heart, liver, spleen, lung, kidney sections of mice could produced histopathological changes; The immunohistochemistry was used for lung sections to detect the JSRV envelope protein in mice lung tissue.Results showed that the experiment successfully constructed recombinant eukaryotic expression plasmid pcDNA3.1(+)/exJSRV-env; The recombinant plasmid was transiently transfected into NIH3T3 cells, formed the transformed foci and leaded to the malignant transformation. The transfected cells were injected into nude mice and induced tumorigenesis in nude mice; H.E staining showed that injection caused varying degrees of damage changes in each organ. The immunohistochemistry for mice lung found the positive signal of JSRV env protein expression. This study shows that Jaagsiekte sheep retrovirus envelopeprotein can cause the malignant transformation of the NIH3T3 cells, and expresses successfully in the lung of mice, this study is to further explore the structure and function of Inner Mongolia strains of exogenous Jaagsiekte sheep retrovirus envelope protein and provides an experimental basis on its pathogenic mechanism and tumorigenic role.