We measured the differentiation potential of the Bptf knockout ES cells in vitro as embryoid bodies and in vivo as teratomas. Bptf wild type and two independent knockout cell lines were subcutaneously injected into NOD/SCID mice and allowed to form teratomas over 8 weeks. Wild type ES cells formed teratomas in 8/11 injected mice. Bptf knockout lines did not form any observable tumors in 10 injections (data not shown). This study demonstrated that Bptf is essential for one or more biological processes including cell viability, proliferation or differentiation in the animal.
