Institute of Animal Biotechnology, College of Animal Science and Technology, Shanxi Agricultural University, Taigu, PR China.
Acta Histochem. 2012 Sep;114(5):429-33. doi: 10.1016/j.acthis.2011.08.003. Epub 2011 Sep 3.
The transforming growth factor beta (TGF-β) superfamily exerts a wide range of effects on biological events, including spermatogenesis. Smad proteins are downstream signal mediators, which transduce TGF-β signals from the cell surface to the nucleus. Smad4 protein is the common transducer of the TGF-β superfamily that participates in the signaling of all the members of TGF-β superfamily. Smad4 is expressed in the mammalian testis and is believed to play an important role during testicular development and spermatogenesis. Information about Smad4 distribution and function in the testis of birds, including the domestic fowl, is still unclear. In the current study, our objective was to clarify the signal transduction pathway of the TGF-β superfamily in the regulation of testicular development and spermatogenesis by investigating the expression of Smad4 protein in the testis of newborn, prepuberty, puberty and adult domestic fowl. Cellular localization of Smad4 was determined by immunohistochemistry. Our study revealed that the Smad4 was widely expressed in the fowl testis, mainly immunolocalized in the cytoplasm of Sertoli cells, Leydig cells and germ cells. The presence of Smad4 protein in these testicular cells provides molecular and morphological evidence for TGF-β signal transduction during testicular development and spermatogenesis.
转化生长因子β（TGF-β）超家族对包括精子发生在内的许多生物学事件发挥广泛作用。Smad 蛋白是下游信号转导介质，将 TGF-β信号从细胞表面传递到细胞核。Smad4 蛋白是 TGF-β超家族的共同转导蛋白，参与 TGF-β超家族所有成员的信号转导。Smad4 在哺乳动物睾丸中表达，并被认为在睾丸发育和精子发生中发挥重要作用。关于 Smad4 在鸟类睾丸中的分布和功能的信息，包括家禽，仍然不清楚。在本研究中，我们的目的是通过研究 Smad4 蛋白在家禽新生、性成熟前期、性成熟和成年睾丸中的表达，阐明 TGF-β 超家族在睾丸发育和精子发生中的信号转导途径。通过免疫组织化学法确定 Smad4 的细胞定位。我们的研究表明，Smad4 在禽类睾丸中广泛表达，主要免疫定位于支持细胞、间质细胞和生殖细胞的细胞质中。这些睾丸细胞中 Smad4 蛋白的存在为 TGF-β信号转导在睾丸发育和精子发生过程中的作用提供了分子和形态学证据。
