Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA.
J Cell Biol. 2011 Mar 21;192(6):939-48. doi: 10.1083/jcb.201010104. Epub 2011 Mar 14.
The immortal and totipotent properties of the germ line depend on determinants within the germ plasm. A common characteristic of germ plasm across phyla is the presence of germ granules, including P granules in Caenorhabditis elegans, which are typically associated with the nuclear periphery. In C. elegans, nuclear pore complex (NPC)-like FG repeat domains are found in the VASA-related P-granule proteins GLH-1, GLH-2, and GLH-4 and other P-granule components. We demonstrate that P granules, like NPCs, are held together by weak hydrophobic interactions and establish a size-exclusion barrier. Our analysis of intestine-expressed proteins revealed that GLH-1 and its FG domain are not sufficient to form granules, but require factors like PGL-1 to nucleate the localized concentration of GLH proteins. GLH-1 is necessary but not sufficient for the perinuclear location of granules in the intestine. Our results suggest that P granules extend the NPC environment in the germ line and provide insights into the roles of the PGL and GLH family proteins.
生殖系的不朽和全能特性取决于生殖质内的决定因素。跨门生殖质的一个共同特征是存在生殖颗粒，包括秀丽隐杆线虫中的 P 颗粒，其通常与核周相关。在秀丽隐杆线虫中，核孔复合物（NPC）样 FG 重复结构域存在于与 VASA 相关的 P 颗粒蛋白 GLH-1、GLH-2 和 GLH-4 以及其他 P 颗粒成分中。我们证明 P 颗粒与 NPC 一样，是通过弱疏水相互作用结合在一起的，并建立了一个大小排除屏障。我们对肠表达蛋白的分析表明，P 颗粒，像 NPC 一样，GLH-1 及其 FG 结构域不足以形成颗粒，但是需要像 PGL-1 这样的因子来引发 GLH 蛋白的局部浓度。GLH-1 对于 P 颗粒在肠中的核周位置是必要的，但不是充分的。我们的结果表明，P 颗粒扩展了生殖系中的 NPC 环境，并为 PGL 和 GLH 家族蛋白的作用提供了线索。
