MKK7-mediated phosphorylation of JNKs regulates the proliferation and apoptosis of human spermatogonial stem cells

Figure 1 Mitogen-activated protein kinase kinase 7 was mainly expressed in human spermatogonial stem cells. A: Mitogen-activated protein kinase kinase 7 (MKK7) was detected in samples from 2 patients with obstructive azoospermia (OA) using western blotting; B: Hematoxylin-eosin staining of testis with normal spermatogenesis; C: Immunohistochemistry revealing the cellular localization of MKK7 in normal testis; D: Double immunostaining showing the co-expression of MKK7 with DEAD-box helicase 4 (DDX4), glial cell line-derived neurotrophic factor family receptor alpha 1 (GFRA1) and proliferating cell nuclear antigen (PCNA) in normal human testis and the proportion of MKK7+ cells with DDX4, GFRA1 and PCNA expression; at least 20 seminiferous tubules were counted. Scale bars in B, C, and D: 50 μm. ACTB: Beta actin.