Yagi T, Tokunaga T, Furuta Y, Nada S, Yoshida M, Tsukada T, Saga Y, Takeda N, Ikawa Y, Aizawa S
Laboratory of Molecular Oncology, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan.
Anal Biochem. 1993 Oct;214(1):70-6. doi: 10.1006/abio.1993.1458.
In producing mutant mice by gene-targeting and gene-trapping in embryonic stem (ES) cells, the efficient colonization of the mutant ES cells into germline is still a critical matter. We have established a new line of ES cells, TT2, from an F1 embryo between a C57BL/6 female and a CBA male. When the TT2 cells were injected into blastocysts, the colonization into each tissue was very low. However, when injected into eight-cell embryos, the cells segregated inside the blastomeres, localized in an inner cell mass of blastocysts developed 1 day later, and colonized efficiently in each tissue of the pups. The pups were disproportionately male, about half of which were composed of TT2-derived cells primarily; in more than 70% of the males, TT2-derived cells were dominant, accounting for over half of the total cells. When these males were mated, they exclusively yielded TT2-derived offspring. The germline-differentiating potency was stable during 3 weeks of culture. Twenty-one of 24 mutant clones independently isolated yielded germline chimeras, and 19 clones yielded them in a rate comparable to that of the parent cells. Thus, TT2 cells can serve as a valuable vehicle for the production of mutant mice.
在通过基因靶向和基因捕获在胚胎干细胞（ES细胞）中产生突变小鼠时，突变ES细胞向种系的有效定殖仍然是一个关键问题。我们从C57BL/6雌性和CBA雄性之间的F1胚胎中建立了一个新的ES细胞系TT2。当将TT2细胞注射到囊胚中时，其在各个组织中的定殖率非常低。然而，当将其注射到八细胞胚胎中时，这些细胞在卵裂球内分离，定位在1天后发育的囊胚的内细胞团中，并在幼崽的各个组织中高效定殖。幼崽中雄性比例过高，其中约一半主要由TT2来源的细胞组成；在超过70%的雄性中，TT2来源的细胞占主导地位，占总细胞数的一半以上。当这些雄性交配时，它们只产生TT2来源的后代。在3周的培养过程中，种系分化能力保持稳定。独立分离的24个突变克隆中有21个产生了种系嵌合体，19个克隆产生种系嵌合体的比率与亲代细胞相当。因此，TT2细胞可作为产生突变小鼠的有价值载体。
