Fig 3.

Experimental design for generating mouse EG cells from an interspecific cross. Day 8.5 (129/SvEv × CAST/Ei)F₁ embryos were dissected near the base of the allantois to initiate primordial GC cultures from which EG cell lines were established, which was confirmed by s.c. injection into athymic nude mice to form teratocarcinomas, and by blastocyst injection to generate chimeric mice capable of germ-line transmission. The EG cell lines could be induced to differentiate in vitro by any of several methods, including transfection with a vector selectable after cardiomyocyte differentiation. RA, retinoic acid. In addition, cells differentiated in vivo in chimeric mice could be flow-sorted by prior transfection with a GFP-containing vector.