Interplay of PIWI/Argonaute protein MIWI and kinesin KIF17b in chromatoid bodies of male germ cells
Interplay of PIWI/Argonaute protein MIWI and kinesin KIF17b in chromatoid bodies of male germ cells
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DOI：
10.1242/jcs.03022
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发表时间：
2006-07-01
影响因子：
4
通讯作者：
Sassone-Corsi, Paolo
中科院分区：
文献类型：
--
作者：
Kotaja, Noora;Lin, Haifan;Sassone-Corsi, Paolo
类染色质体被认为是存储和处理单倍体转录本的雄性生殖细胞特异性平台。控制这些生殖细胞特异性结构的形成和功能的分子机制仍然难以捉摸。在这项研究中，我们发现驱动蛋白运动蛋白 KIF17b 定位于类染色体中，该蛋白参与 RNA 和转录共激活因子的核质转运。类染色质体在圆形精子细胞的细胞质中主动且非随机地移动，与核膜频繁接触。因此，KIF17b 的定位为类染色体的微管依赖性移动以及特定成分进出类染色体的运输提供了潜在的机制。有趣的是，我们证明 KIF17b 与 PIWI/Argonaute 家族睾丸特异性成员 MIWI（参与 RNA 代谢的类染色质体的组成部分）发生物理相互作用。将单倍体 RNA 加载到类染色体中可能需要 KIF17b 和 MIWI 之间的功能相互作用。重要的是，来自 miwi 缺失小鼠的圆形精子细胞的类染色质体并未完全压缩，仍以弥散的类染色质物质形式存在，这揭示了 MIWI 在类染色质体形成中所起的重要作用。这些结果为类染色体在单倍体生殖细胞基因表达转录后调控中的功能提供了新的线索。
Chromatoid bodies are thought to act as male-germ-cell-specific platforms for the storing and processing of haploid transcripts. The molecular mechanisms governing the formation and function of these germ-cell-specific structures have remained elusive. In this study, we show that the kinesin motor protein KIF17b, which is involved in the nucleocytoplasmic transport of RNA and of a transcriptional coactivator, localizes in chromatoid bodies. The chromatoid body moves actively and non-randomly in the cytoplasm of round spermatids, making frequent contacts with the nuclear envelope. The localization of KIF17b thereby offers a potential mechanism for microtubule-dependent mobility of chromatoid bodies, as well as for the transport of the specific components in and out of the chromatoid body. Interestingly, we demonstrate that KIF17b physically interacts with a testis-specific member of the PIWI/Argonaute family, MIWI, a component of chromatoid bodies implicated in RNA metabolism. A functional interplay between KIF17b and MIWI might be needed for the loading of haploid RNAs in the chromatoid body. Importantly, chromatoid bodies from round spermatids of miwi-null mice are not fully compacted and remain as a diffuse chromatoid material, revealing the essential role played by MIWI in the formation of chromatoid bodies. These results shed new light on the function of chromatoid bodies in the post-transcriptional regulation of gene expression in haploid germ cells.