人乳铁蛋白(hLF)转基因山羊的遗传背景分析

以随机整合方式获得的转基因动物外源基因的拷贝数、整合位点及染色体核型等遗传背景并不清楚,可能会存在外源基因的沉默整合、无效整合、毒性整合以及其表达水平不可预测等问题。文中选取了6只原代(F0)及其相对应的子一代(F1)的人乳铁蛋白(hLF)转基因山羊作为研究对象,分别颈静脉采血、提取DNA,通过染色体核型分析、实时荧光定量PCR(qPCR)、ELISA和Westernblotting等检测技术,研究其外源基因的遗传背景与表达水平。结果显示,6只F0代转基因山羊的染色体没有明显的形态变异、数量改变等异常情况。相对拷贝数高低不同(2–16),且能够稳定地遗传给下一代,F0和F1代hLF基因拷贝数一致。F1代转基因山羊表达hLF水平最高可达1.12 g/L(L3-1,拷贝数8)。结果表明,整合的外源基因能够稳定地遗传下一代,也没有对转基因山羊个体的生长发育造成障碍,而且拷贝数高低与hLF表达水平无明显的相关性,这为转基因山羊及其他转基因动物的新品种培育奠定了基础,解析了遗传背景。

Genetic background of human lactoferrin transgenic goats

The genetic background such as copy number, integration site and chromosome karyotype of exogenous genes of transgenic animals obtained by random integration is still unclear. There may be some problems such as silent integration, invalid integration, toxic integration and unpredictable expression level of exogenous genes. In this study, six primary(F0) and their corresponding offspring(F1) of human lactoferrin(hLF) transgenic goats were selected as the research objects, and blood samples were collected from jugular vein and DNA were extracted. The genetic background and expression level of exogenous genes were studied by chromosome karyotype analysis, real-time quantitative PCR(qPCR), ELISA and Western blotting. The chromosomes of six F0 transgenic goats had no obvious morphological variation, number change and other abnormalities. The relative copy number was different(2–16) and could be steadily inherited to the next generation. The copy number of F0 and F1 hLF gene was the same. The highest expression level of hLF was 1.12 g/L in F1 transgenic goats(L3-1, 8 copies). The results proved that the integrated exogenous genes could steadily inherit the next generation, and did not cause obstacles to the growth and development of transgenic goat individuals. Moreover, there was no obvious correlation between the number of copies and the expression level of hLF. This laid a foundation for the new varieties cultivation of transgenic goats and other transgenic animals, and analysis of genetic background.