Department of Chemistry, Jinan University, Guangzhou 510632, People's Republic of China.
Gene. 2012 Mar 10;495(2):189-93. doi: 10.1016/j.gene.2011.12.044. Epub 2012 Jan 3.
Spermatogonial stem cells (SSCs) provide the foundation for spermatogenesis and male fertility. However, spermatogenesis has direct links with some adhesion molecules on SSCs membrane. Β1-integrin (CD29) is such a kind of adhesion molecule and a biomarker of pig's SSCs. Therefore, quantitative characteristics of β1-integrin expression level in a single cell could help us to capture the signal switch and understand the mechanism of spermatogenesis. In this study, atomic force microscopy (AFM) was used to obtain the morphology and ultrastructure of SSCs at nanometer level, and the CD29 Ab-functionalized AFM tip was used to examine β1-integrin distribution on the cell membrane. There were many force-binding spots on about 50% of cell membrane binding to the CD29 Ab-functionalized AFM tip, and the mean bind rupture force was 283.63±12.56PN which was much larger than the non-specific average force 70.75±10.95PN. Meanwhile, β1-integrin on SSCs membrane was distributed non-uniformly, and there were some β1-integrins appeared to be expressed as 150-350 nm nanoclusters on the membrane. Our results discovered the structure of SSCs at nanometer level by AFM. The force between β1-integrin antigen-antibody interactions and the distribution of β1-integrin protein on SSCs membrane were also firstly demonstrated.
精原干细胞（SSC）为精子发生和雄性生育力提供了基础。然而，精子发生与 SSCs 膜上的某些黏附分子直接相关。Β1-整合素（CD29）就是这样一种黏附分子，也是猪 SSCs 的标志物。因此，单个细胞中β1-整合素表达水平的定量特征可以帮助我们捕捉信号开关，了解精子发生的机制。在本研究中，原子力显微镜（AFM）用于获取 SSCs 的纳米级形态和超微结构，并用 CD29 Ab 功能化的 AFM 探针检测细胞膜上β1-整合素的分布。约 50%的细胞膜与 CD29 Ab 功能化的 AFM 探针结合，有许多力结合点，平均结合断裂力为 283.63±12.56PN，远大于非特异性平均力 70.75±10.95PN。同时，SSC 膜上的β1-整合素分布不均匀，有些β1-整合素似乎在膜上呈现出 150-350nm 的纳米簇。我们的研究结果通过 AFM 发现了 SSCs 的纳米级结构。首次证明了 SSCs 膜上β1-整合素抗原抗体相互作用的力以及β1-整合素蛋白的分布。
