不同小鼠品系囊胚受体对 C57 BL／6胚胎干细胞种系嵌合效率的影响

摘要

Objective To improve the gene targeting efficiency with C57BL/6 embryonic stem ( ES) cells.Meth-ods Three different genetically modified C57BL/6 ES cell lines, named TLX3, Ai3K and SL, were microinjected into ICR, B6( Cg)-Tyrc-2J and BALB/c mouse blastocysts, respectively.The efficiency was statistically evaluated according to three aspects:blastocyst collection, chimera production and germline transmission.Results None of the three ES cell lines was germline transmitted with B6(Cg)-Tyrc-2J mice as blastocyst donors, while it was achieved with both BALB/c and ICR mouse blastocysts.Compared in the aspect of blastocysts collection, ICR mouse was much better than BALB/c mouse (P<0.05), and the chimera production efficiency of ICR mouse was comparable to that of BALB/c mouse (P =0.115). As to the germline transmission efficiency, that of BALB/c mice is significantly higher than that of the ICR mice ( P<0.01).Conclusions The germline transmission efficiency of BALB/c mouse is highest among these three mouse strains. However, it has the disadvantages of blastocyst collection, developmental delay and zona pellucida fragility, compared with ICR mouse.Therefore, ICR mouse is also a good candidate as blastocyst donor for embryonic stem cell microinjection.%目的：考察不同品系的小鼠囊胚对C57 BL／6胚胎干细胞种系嵌合效率的影响，进而提高通过在C57BL／6胚胎干细胞中同源重组制作基因打靶小鼠的效率。方法选取近交系B6（Cg）-Tyrc-2J和BALB／c品系及封闭群ICR作为囊胚供体鼠，通过在TLX3、Ai3K和SL三个不同基因修饰ES细胞的种系嵌合实验中，平行比较三者的囊胚利用率、嵌合鼠获得效率以及种系遗传效率等三个方面，并进一步针对囊胚来源这一因素对效率的影响进行统计学分析。结果三种ES细胞均未能通过B6（Cg）-Tyrc-2J品系囊胚的注射获得种系遗传。而BALB／c品系与ICR品系相比，囊胚利用率明显低于ICR品系（P＜0.05）；嵌合鼠获得效率方面，BALB／c与ICR相当（P＝0.115）；而种系遗传效率方面，BALB／c品系显著高于其他品系（P＜0.01）。结论 BALB／c品系在C57BL／6胚胎干细胞种系嵌合效率方面确实具有优势，然而，由于BALB／c囊胚较难获得，并且存在发育延迟和透明带脆性高等问题，而ICR品系在囊胚获得和利用方面的效率明显高于BABL／c，并且也可以支持C57BL／6胚胎干细胞的种系遗传，因此也是C57BL／6胚胎干细胞囊胚注射中较好的选择。