Pan Jieyan, Goodheart Mary, Chuma Shinichiro, Nakatsuji Norio, Page David C, Wang P Jeremy
Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Development. 2005 Sep;132(18):4029-39. doi: 10.1242/dev.02003. Epub 2005 Aug 10.
Nuages are found in the germ cells of diverse organisms. However, nuages in postnatal male germ cells of mice are poorly studied. Previously, we cloned a germ cell-specific gene named Rnf17, which encodes a protein containing both a RING finger and tudor domains. Here, we report that RNF17 is a component of a novel nuage in male germ cells--the RNF17 granule, which is an electron-dense non-membrane bound spherical organelle with a diameter of 0.5 mum. RNF17 granules are prominent in late pachytene and diplotene spermatocytes, and in elongating spermatids. RNF17 granules are distinguishable from other known nuages, such as chromatoid bodies. RNF17 is able to form dimers or polymers both in vitro and in vivo, indicating that it may play a role in the assembly of RNF17 granules. Rnf17-deficient male mice were sterile and exhibited a complete arrest in round spermatids, demonstrating that Rnf17 encodes a novel key regulator of spermiogenesis. Rnf17-null round spermatids advanced to step 4 but failed to produce sperm. These results have shown that RNF17 is a component of a novel germ cell nuage and is required for differentiation of male germ cells.
在多种生物体的生殖细胞中都能发现类核体。然而，对于小鼠出生后雄性生殖细胞中的类核体研究较少。此前，我们克隆了一个生殖细胞特异性基因Rnf17，它编码一种同时含有RING结构域和 tudor结构域的蛋白质。在此，我们报告RNF17是雄性生殖细胞中一种新型类核体——RNF17颗粒的组成成分，RNF17颗粒是一种电子致密的非膜结合球形细胞器，直径为0.5微米。RNF17颗粒在粗线期晚期和双线期精母细胞以及伸长的精子细胞中很突出。RNF17颗粒与其他已知的类核体，如拟染色体体不同。RNF17在体外和体内都能够形成二聚体或聚合物，这表明它可能在RNF17颗粒的组装中起作用。Rnf17基因缺失的雄性小鼠不育，并且在圆形精子细胞阶段完全停滞，这表明Rnf17编码一种新型的精子发生关键调节因子。Rnf17基因缺失的圆形精子细胞发育到第4阶段，但未能产生精子。这些结果表明，RNF17是一种新型生殖细胞类核体的组成成分，是雄性生殖细胞分化所必需的。
