Pluripotency of ES cells derived from tetraploid embryo complemented male mice

Pluripotent mouse embryonic stem (ES) cells have the ability to generate completely ES cell-derived mice by tetraploid (TE-4N) complementation although; derivation of ES cells from TE-4N animals has not been well defined. In this study, we generated TE-4N mice from high passage number ES cells and, in turn, determined the possibility of deriving ES cells from the TE-4N mice. The results showed that adult fertile TE-4N mice could be generated by aggregation of tetraploid embryos using ES cells passaged 23 times. Furthermore, ES cells could be derived from the TE-4N male mice and as judged by molecular characterisation and a study of chimeras, these ES cells were pluripotent. The findings demonstrate that tetraploid complementation is an efficient way to produce fertile mice, which can then give rise to pluripotent ES cells.