心脏特异表达Dhcr24转基因小鼠的建立和表型分析

The Establishment of Heart-specific Dhcr24 Transgenic Mice

目的建立心脏特异表达小鼠24-脱氢胆固醇还原酶基因(Dhcr24)转基因小鼠,研究该基因在心脏中表达对小鼠心脏发育,形态和功能维持中的作用。方法RT-PCR法克隆小鼠24-脱氢胆固醇还原酶基因,把Dhcr24基因插入-αMHC启动子下游,构建转基因表达载体,通过显微注射法建立Dhcr24 C57BL/6J转基因小鼠。并利用特异引物PCR法鉴定转基因小鼠的基因型,RT-PCR和Western Blotting检测基因表达水平,光学显微镜和超声检测不同月龄Dhcr24转基因小鼠心脏的组织结构改变。结果建立了2个品系的心脏特异表达Dhcr24转基因小鼠。转入的Dhcr24基因在心脏组织的表达水平超过内源性Dhcr24的3倍。心脏组织学和超声检查证实:Dhcr24转基因小鼠的心室壁变厚,心腔变小,但心脏功能保持正常。结论成功建立了心脏特异表达Dhcr24转基因小鼠,Dhcr24基因在心脏组织的过度表达对小鼠心脏发育和功能维持中的作用需要进一步探讨。

Objective To generate the 24-dehydrocholesterol reductase gene （Dhcr24） transgenic mice and investigate its functions on heart development and maintenance. Method Dhcr24 gene was cloned form mouse with RT-PCR and identified with sequencing analysis. Dhcr24 gene was inserted down stream of α-MHC promoter to construct the vector which express at cardiac tissue specially. The transgenic mice were produced by microinjection method and the genotype was detected by PCR. The expression levels of the transgene were detected by both RT-PCR and Western blotting. The histological and function changes of the heart of the transgenic mice were analyzed by microscope observation and echocardiography analysis. Results Two lines of C57BL/6J transgenic mice of Dhcr24 gene were established. The expression levels of the Dhcr24 gene were over 3-fold of the endogenous Dhcr24 in the heart tissues. The ten to twelve-month old Dhcr24 transgenic mice showed their hearts with deeper ventricular wall and reduced ventricular chamber compared with those of the wild controls revealed by histology and echocardiography analysis. Conclusion The heart specific Dhcr24 transgenic mice were established successfuUy. The function of Dhcr24 gene in development and maintenance of the morphology and function of normal heart needs further investigating.