Nuclear expression of POU5F1 (arrowheads) was observed in BMP7-stimulated HS360 cells after two weeks in culture (A), as well as in undifferentiated hES cells cultured on hFFs (C). Cytoplasmic expression (arrows) of DDX4 (D), VIMENTIN (G) and AMH (J) was present in BMP7-stimulated HS360 cells and human testicular tissue (F, I and L). Negative controls exhibited no specific staining in either the nucleus or cytoplasm (B, E, H and K; and inserts in C, F, I and L). The organization of Sertoli-like cells among stimulated HS360 cells (red arrow heads in M) and Sertoli cells in the one-year-old human testis (red arrow heads in N) was similar. Scale bars: 100 μm in B, C, E, H, K, M and N and the insert in C; 50 μm in F, I and L and the other inserts; 20 μm in A, D, G and J. Abbreviations: AMH: anti-Mullerian hormone, PAS: periodic acid-Schiff. For an explanation of the other abbreviations, see the legend to Fig 2.