疾病动物模型,基因修饰白血病 z-bio 2021-12-27 363

　　[Modeling mechanism] bcr/abl transgenic mouse model: Through cloning and analysis of the promoter sequence and function of the mouse Tec gene, it was found that the genes regulated by the Tec promoter are only specifically expressed in the cytoplasm of hematopoietic stem cells. The promoter sequence of the mouse Tec gene is used to prepare a transgenic vector carrying the leukemia-related gene ber/abl to prepare a transgenic animal. Transgenic mice first developed abnormal granulocyte proliferation and hyperthrombocytoemia, and developed myeloproliferative syndrome after a certain period of time, which is very similar to human CML. Among them, transgenic mice showed acute leukemia after birth, but their offspring showed myelodysplastic syndrome after a period of incubation. Another type of transgenic mouse is a highly-expressed continuously activated mutant Stats. This mutant stats carries 2 mutation sites and can bind to endogenous stat5 to form a dimer, which is continuously activated. Leukemia occurs during the growth and development of this kind of mice. There are also knock-in models of mutant genes. For example, SHP-2D61G and SHP-2E76K gene knock-in mice all developed leukemia.

　　[Model Features] Several transgenic mouse strains that can mimic human CML have been established using different promoters. Compared with the CML model established by retroviral transfection and transplantation, the transgenic mouse model has the following advantages: ① The bcr/abl gene is expressed in the body as a part of the transgenic mouse, which can more accurately simulate human CML; and The CML model established by retroviral transfection and transplantation is affected by many cytokines during cell culture and transplantation. These cytokines and other factors in the treatment of recipient mice have a greater impact on the phenotype of the disease. ②Bcr/abl transgenic mice can be passaged, but the CML model established by retrovirus transfection and transplantation must be re-established. ③The transgenic CML model has a certain incubation period, which is very similar to human CML; while the CML model established by retroviral transfection and transplantation has a short incubation period, which is not conducive to the study of the pre-pathogenesis of human CML. ④ The CML of transgenic mice has monoclonality similar to human CML, while the CML of retrovirus transfected and transplanted mice is polyclonal. Transgenic CML also has some shortcomings: ①Bcr/abl gene expression is expressed in every cell of transgenic animals, while human CML is only expressed in hematopoietic stem cells and progenitor cells, which may affect the pathological characteristics and treatment of CML; ②SHP -2D61G mice only develop myeloid proliferative disease during normal growth and development, but leukemia and other tumors occur after irradiation; ③SHP-2E76K is a conditional knock-in mouse. If the blood system of embryonic mice expresses SHP-2E76K mutation, it will cause Mouse embryos are lethal, so only after the mouse is born, Poly I:C is used to induce the expression of Cre in the blood system, resulting in mouse hematopoietic stem cells or progenitor cells expressing the SHP-2E76K mutant protein, and the mouse develops leukemia.

　　[Model evaluation and application] Because the bcr/abl transgenic mouse model has shortcomings such as insufficient genetic stability and insufficient accuracy in mimicking CML, it is necessary to find more suitable promoters, explore more convenient methods of transgenic animals, and try more similar ones. Animal breeds. At present, it is mainly used for the following three researches: to confirm whether CML is hematopoietic stem cell-derived, to study the joint effect of ber/abl gene and other related genes on leukemia, and to screen therapeutic drugs. SHP-2D61G and SHP-2E76K knock-in mice are good animal models of leukemia, but they need to be commercialized.