Ccnd1 deficiency suppresses aberrant pluripotency in teratoma-susceptible gonocytes. (A) Oct4::GFP transgenic M19-Ccnd1 WT and KO embryonic testes were sectioned and immunostained for NANOG (E13.5, E14.5, E15.5). GFP-positive germ cells, positive and negative for NANOG, were counted. Data are plotted as the percentage of germ cells positive for NANOG ± SEM (n = 4-13). ‡, P < 0.001; #, P < 0.0001. (B) Confocal microscopy images of E15.5 Oct4::GFP transgenic M19-Ccnd1 WT and KO gonads immunostained for NANOG. Small groups of NANOG-positive germ cells are noted (arrowheads). Scale bar: 50 μm.