Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
Mol Cell Endocrinol. 2011 Feb 20;333(2):134-42. doi: 10.1016/j.mce.2010.12.021. Epub 2010 Dec 22.
We identified Ran-binding protein 17 (RANBP17) as one of the interacting partners of sperm maturation 1 (SPEM1) using yeast 2-hybrid screening and immunoprecipitation assays. Expression profiling analyses suggested that RANBP17 was preferentially expressed in the testis. Immunofluorescent confocal microscopy revealed a dynamic localization pattern of RANBP17 during spermatogenesis. In primary spermatocytes RANBP17 was mainly localized to the XY body. In the subsequent spermiogenesis, RANBP17 was first observed in the nuclei of round spermatids (steps 1-7) and then confined to the manchette of elongating spermatids (steps 8-14) together with its interacting partner SPEM1. In the Spem1-null testes, levels of RANBP17 were significantly elevated. As a member of a large protein family involved in the nucleocytoplasmic transport, RANBP17 may have a role in sex chromosome inactivation during the meiotic phase of spermatogenesis, and also in the intramanchette transport during spermiogenesis. Interactions between RANBP17 and SPEM1, for the first time, point to a potential function of SPEM1 in the RANBP17-mediated nucleocytoplasmic transport.
我们使用酵母双杂交筛选和免疫沉淀实验鉴定出 Ran 结合蛋白 17（RANBP17）是精子成熟 1（SPEM1）的一个相互作用伙伴。表达谱分析表明 RANBP17 优先在睾丸中表达。免疫荧光共聚焦显微镜显示 RANBP17 在精子发生过程中有一个动态的定位模式。在初级精母细胞中，RANBP17 主要定位于 X-Y 体。在随后的精子形成过程中，RANBP17 首先在圆形精子细胞的核中被观察到（步骤 1-7），然后与它的相互作用伙伴 SPEM1 一起局限于伸长精子细胞的顶体（步骤 8-14）。在 Spem1 缺失的睾丸中，RANBP17 的水平显著升高。作为参与核质转运的一个大型蛋白家族的成员，RANBP17 可能在精子发生的减数分裂阶段的性染色体失活中发挥作用，也可能在精子形成过程中的顶体运输中发挥作用。RANBP17 和 SPEM1 的相互作用首次表明 SPEM1 在 RANBP17 介导的核质转运中具有潜在功能。
