Figure 5. Rac1 Function in Sertoli Cells Is Dispensable for the Maintenance of Undifferentiated Spermatogonia.

(A–N) Seven-month-old control Dhh-Cre;Rac1^flox/+ (A, C, E, G, I, K, and M) and Dhh-Cre;Rac1^flox/flox cKO (B, D, F, H, J, L, N) testes. (C’), (D’), (K’), and (L’) are higher-magnification images of the boxed regions in (C), (D), (K), and (L). Dashed outlines indicate tubule boundaries.

(A and B) Relative to controls (A), cKO testes (B) have smaller tubules, containing a variable number of TRA98⁺ germ cells.

(C–H) Similar to controls (C, E, and G), cKO testes (D, F, and H) still have GFRA1⁺ and ZBTB16⁺ undifferentiated spermatogonia within tubules (arrows in C–F); cKO testes also contain a variable number of DDX4⁺ germ cells, albeit in reduced numbers.

(I–L) As in controls (I and K), cKO testes (J and L) contain STRA8⁺ differentiating spermatogonia and spermatocytes (asterisks in I and J), as well as KIT⁺ differentiating spermatogonia (arrows in K’ and L’).

(M and N) Relative to controls (M), cKO tubules (N) have a reduced, variable number of H1T⁺ spermatocytes and round spermatids. Thin scale bar, 100 μm; thick scale bar, 25 μm.