F-box and WD domain protein 7 (FBXW7) is reported to bind with c-Myc in mouse spermatogonial stem cells, regulating self-renewal; however, the pattern and stage of expression of FBXW7 in human testes are unclear. In the present study, we examined the expression of human FBXW7 in adult testis, and analyzed fixed sections from adult testes and fetal testes to determine the cell type-specific expression pattern of FBXW7. The results showed that FBXW7α and FBXW7β genes are expressed in the testis; however, only FBXW7α protein could be detected. FBXW7 was not detected in human spermatogonial stem cells. Interestingly, FBXW7 was mainly expressed in the cell nuclei of later stage germ cells and differentiated somatic cells. We also observed high FBXW7 expression in human fetal germ cells, particularly in prespermatogonia. Our results raised the possibility that FBXW7 has different functions in humans and mice. The cell type-specific expression pattern of FBXW7 suggests that it performs regulatory functions during the late stage of human spermatogenesis instead of being involved in the self-renewal of spermatogonial stem cells.

中文翻译：

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FBXW7在人睾丸中的表达特征表明其功能与小鼠不同。

据报道，F-box和WD域蛋白7（FBXW7）在小鼠精原干细胞中与c-Myc结合，调节自我更新。然而，尚不清楚FBXW7在人睾丸中的表达方式和表达阶段。在本研究中，我们检查了人FBXW7在成年睾丸中的表达，并分析了成年睾丸和胎儿睾丸的固定切片，以确定FBXW7的细胞类型特异性表达模式。结果表明，FBXW7α和FBXW7β基因在睾丸中表达。但是，只能检测到FBXW7α蛋白。在人类精原干细胞中未检测到FBXW7。有趣的是，FBXW7主要在后期生殖细胞和分化的体细胞的细胞核中表达。我们还观察到人类胎儿生殖细胞，特别是在精原细胞形成中高FBXW7表达。我们的结果提出了FBXW7在人和小鼠中具有不同功能的可能性。FBXW7的细胞类型特异性表达模式表明，它在人类精子发生的晚期阶段执行调节功能，而不是参与精原干细胞的自我更新。