Presence of mitochondria-type ribosomes outside mitochondria in germ plasm of Drosophila embryos
Presence of mitochondria-type ribosomes outside mitochondria in germ plasm of Drosophila embryos
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DOI：
10.1073/pnas.171286998
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发表时间：
2001-07-31
影响因子：
11.1
通讯作者：
Kobayashi, S
中科院分区：
文献类型：
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作者：
Amikura, R;Kashikawa, M;Kobayashi, S
线粒体编码的大小核糖体RNA（mtlrRNA和mtsrRNA）被运输出线粒体到极性颗粒，这是果蝇生殖质的独特细胞器。线粒体外mtlrRNA数量的减少导致胚胎不能形成生殖系祖细胞或极细胞，这表明mtlrRNA沿着mtsrRNA在极粒上起作用以指定生殖系。在这项研究中，我们提供了几条线的证据表明，在极细胞形成之前的一段短时间内，有极颗粒上的核糖体。我们的超微结构分析表明，这些核糖体包括线粒体rRNA和至少两个线粒体核糖体蛋白（S12和L7/L12）。此外，这些核糖体整合到极性颗粒表面发育良好的多聚核糖体中。我们认为，翻译依赖于转录型核糖体是一个重要的机制，生殖系的形成。
Mitochondrially encoded large and small ribosomal RNAs (mtlrRNA and mtsrRNA) are transported out of mitochondria to polar granules, the distinctive organelles of germ plasm in Drosophila. Reduction of the extramitochondrial mtlrRNA amount leads to the failure of embryos to form the germ-line progenitors, or pole cells, suggesting that mtlrRNA, along with mtsrRNA, functions on the polar granules to specify the germ line. In this study, we provide several lines of evidence showing that there are mitochondria-type ribosomes on the polar granules during a short period before pole cell formation. Our ultrastructural analysis reveals that these ribosomes include both mitochondria) rRNAs and at least two mitochondria) ribosomal proteins (S12 and L7/L12). Furthermore, these ribosomes are integrated into well developed polysomes on the surface of polar granules. We propose that translation dependent on mitochondria-type ribosomes is an important mechanism underlying germ-line formation.