Chimeric potency of a mutator strain of mouse teratocarcinoma cells.

The developmental potential of a mutator strain Ara Cr (1.5)4 of mouse teratocarcinoma cells was examined by injecting these cells into host blastocysts. Analysis of developing embryos at 9.5 days of gestation showed the mutator strain gave chimeras at a rate comparable with that of the parent strain. However, most of these chimeric embryos with the mutator strain were abnormal, and the extent of abnormality seems to be related to the proportion of the mutator-derived cells in the embryos. When injected embryos were allowed to develop to 14.5 days, the number of developing embryos decreased, and only a few were chimeric in limited tissues. The results suggest that the mutator strain is lethal to early gestational development, and only those chimeras with limited colonization of the strain can develop normally beyond this stage.