Institute of Animal Biotechnology, College of Animal Science and Technology, Shanxi Agricultural University, Taigu, PR China.
Acta Histochem. 2013 Jan;115(1):16-21. doi: 10.1016/j.acthis.2012.02.007. Epub 2012 Mar 27.
Growth differentiation factor 9 (GDF9) is an oocyte-derived factor critical for folliculogenesis. Recently, in vitro data showed that GDF9 inhibited the localization of tight junction (TJ) proteins, suggesting that GDF9 could potentially regulate spermatogenesis in vivo, via inhibition of Sertoli cell TJ function. The purpose of the present study was to determine the expression and localization of GDF9, its receptor, ALK5, and its latent target protein, claudin-11 (one of TJ proteins) in adult alpaca testis using Western blot and immunohistochemistry. Western blotting results demonstrated that GDF9, ALK5 and claudin-11 were expressed in the adult alpaca testis. Immunohistochemistry revealed that GDF9 was expressed stage-specifically in the cytoplasm of pachytene spermatocytes and round spermatids of the adult alpaca seminiferous epithelium. Type I receptor, ALK5 was mainly localized in the cytoplasm of round spermatids and Leydig cells, and to a lesser extent in the cytoplasm of pachytene spermatocytes and Sertoli cells. Its latent target protein, claudin-11, was perpendicular or parallel to the basal lamina in the basal part of Sertoli cells. These results indicated that GDF9, as a paracrine and autocrine growth factor derived from round spermatids and pachytene spermatocytes, is involved in regulating spermatogenesis via action on germ cells or somatic cells (i.e. Leydig cells, Sertoli cells).
生长分化因子 9（GDF9）是一种卵母细胞来源的因子，对卵泡发生至关重要。最近的体外数据表明，GDF9 抑制紧密连接（TJ）蛋白的定位，表明 GDF9 可能通过抑制支持细胞 TJ 功能来调节体内精子发生。本研究的目的是使用 Western blot 和免疫组织化学法确定 GDF9、其受体 ALK5 及其潜在靶蛋白紧密连接蛋白 11（TJ 蛋白之一）在成年羊驼睾丸中的表达和定位。Western blot 结果表明 GDF9、ALK5 和 claudin-11 在成年羊驼睾丸中表达。免疫组织化学显示 GDF9 在成年羊驼生精上皮的粗线期精母细胞和圆形精子细胞的细胞质中特异性表达。I 型受体 ALK5 主要定位于圆形精子细胞和间质细胞的细胞质中，在粗线期精母细胞和支持细胞的细胞质中也有少量表达。其潜在靶蛋白紧密连接蛋白 11 在支持细胞的基底部分呈垂直或平行于基底膜。这些结果表明，GDF9 作为一种由圆形精子细胞和粗线期精母细胞衍生的旁分泌和自分泌生长因子，通过作用于生殖细胞或体细胞（即间质细胞、支持细胞）参与调节精子发生。
