Oct-4 protein is present in PUC isolations. Oct-4 detected in the nucleus of PUC cells (n = 3) (A). Faint cytoplasmic fluorescence was detected in some cells (arrowheads), this was not found in all PUC isolates. Nuclear counterstaining (B) revealed Oct-4 staining in virtually every cell when compared to A. No labeling was found when the primary antibody was omitted (C). Nuclear counterstain of control shows lack of nuclear Oct-4 staining (D). No label was seen in porcine fibroblasts (E) or in primary-omitted controls (G). The presence of cells was confirmed with nuclear counterstaining (H). Bar = 50 μM.