At E14.5, Dnd1Ter/Ter germ cells fail to express putative targets P27Kip1 and P21Cip1. ECAD and MVH (red) both mark germ cells. (A-D) P27Kip1 (green) is robustly expressed in both 129/SvJ and C57BL/6J control germ cells (A,B), but is absent in mutant germ cells of both backgrounds (C,D). (E-H) P21Cip1 (green) is also expressed in control germ cells of both backgrounds (E,F), but not in mutants (G,H). P21Cip1 is specific to germ cells; however, note that somatic cells (C,D, arrowheads) express P27Kip1 normally in mutants. Scale bars: 20 μm.