Chemokine CXCL12 and its receptor CXCR4 are not detected in neonatal Amh-cre;Sin3afl/fl testes, while the KIT receptor and cytokine CSF1 distribute normally. Cross-sections of 3-day-old control Amh-cre;Sin3a+/+ (left) and mutant Amh-cre;Sin3afl/fl (right) testes, immunostained with (A): anti-CXCL12 antibody (green), (B): anti-CXCR4 antibody (green), (C): anti-KIT antibody (green), (D): anti-CSF1 antibody (green) and labeled with DAPI (red, A–C). Arrowheads denote Sertoli cell cytoplasm and extracellular regions; arrows identify spermatogonia (A–C) and clusters of Leydig cells in the interstitium (D). Note the lack of CXCL12 and CXCR4 in the seminiferous tubules of the conditional knockout testes. Scale bars represent 25μm (A-C) and 50μm (D).