Xing Xiao-Wei, Li Lu-Yun, Lu Guang-Xiu
Center for Experimental Medical Research, Third Xiangya Hospital of Central South University, Changsha 410013, China.
Yi Chuan. 2007 Jun;29(6):699-704. doi: 10.1360/yc-007-0699.
To understand the function of SRG4, a novel spermatogenesis gene, we studied its expression pattern during normal mouse development and in experimental cryptorchidism. Testis tissues were collected from 1-, 3-, and 12-week-old normal mice and immunohistochemistry was used to detect the expression of SRG4. We performed surgery on mice to cre- ate unilateral cryptorchidism and monitored SRG4 mRNA levels by semi-quantitative RT-PCR in the cryptorchid testis from day 0-18. At post-operative day 18, the cryptorchid testis and the contralateral control testis were harvested and assayed for SRG4 expression by in situ hybridization. Immunohistochemistry results showed that SRG4 protein was hardly detected in 1-week-old mouse testis, but the expression was present in 3-week-old mouse and abundant in 12-week-old mouse testis. SRG4 immunostaining was mainly localized to the cytoplasm and membrane of spermatocytes and round spermatids. Moreover, semi-quantitative RT-PCR result showed the expression of SRG4 mRNA did not decrease until 9 d after cryptorchid surgery, and continued to decline thereafter. In situ hybridization revealed that in contrast to the abundant SRG4 expression in the control side, few remaining germ cells in the crytorchid testis were positive for SRG4 at d 18 after surgery. The results indicated that the expression of SRG4 was regulated by development, and SRG4 was mainly expressed in the cytoplasm of spermatocytes and round spermatids. However, in cryptorchid testis, in which most germ cells undergo apoptosis, only a few of SRG4 is observed, suggesting that SRG4 may be as a specific marker to evaluate the process of spermatogenesis.
为了解新型精子发生基因SRG4的功能，我们研究了其在正常小鼠发育过程及实验性隐睾症中的表达模式。从1周龄、3周龄和12周龄的正常小鼠收集睾丸组织，采用免疫组织化学法检测SRG4的表达。我们对小鼠进行手术以制造单侧隐睾症，并通过半定量逆转录聚合酶链反应（RT-PCR）监测隐睾睾丸从第0天至第18天的SRG4 mRNA水平。在术后第18天，采集隐睾睾丸和对侧对照睾丸，通过原位杂交检测SRG4表达。免疫组织化学结果显示，在1周龄小鼠睾丸中几乎检测不到SRG4蛋白，但在3周龄小鼠中有表达，且在12周龄小鼠睾丸中表达丰富。SRG4免疫染色主要定位于精母细胞和圆形精子细胞的细胞质和细胞膜。此外，半定量RT-PCR结果显示，隐睾手术后直到第9天SRG4 mRNA的表达才下降，此后持续下降。原位杂交显示，与对照侧丰富的SRG4表达相反，术后第18天隐睾睾丸中残留的生殖细胞很少呈SRG4阳性。结果表明，SRG4的表达受发育调控，SRG4主要在精母细胞和圆形精子细胞的细胞质中表达。然而，在大多数生殖细胞发生凋亡的隐睾睾丸中，仅观察到少量SRG4，这表明SRG4可能作为评估精子发生过程的一个特异性标志物。
