IN-VITRO ASSEMBLY OF COILED BODIES IN XENOPUS EGG EXTRACT
IN-VITRO ASSEMBLY OF COILED BODIES IN XENOPUS EGG EXTRACT
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DOI：
10.1091/mbc.5.6.633
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发表时间：
1994-06-01
影响因子：
3.3
通讯作者：
GALL, JG
中科院分区：
文献类型：
--
作者：
BAUER, DW;MURPHY, C;GALL, JG
当去膜的精子核被置于爪蟾卵提取物中时，它们被核膜包围，然后膨胀形成形态上典型的原核。这些核内出现直径小于1.0 μ m至接近3.0 μ m的颗粒。Bell等人通过免疫荧光染色在这些“前核仁体”中鉴定出四种核仁蛋白（纤原蛋白、核仁蛋白、B23/NO38、180-kDa核仁蛋白）。通过原位杂交，我们发现这些小体也含有U3和U8小核rna (snrna)，已知参与前rrna加工。此外，它们包含所有参与pre-mRNA剪接的snrna (U1, U2, U4， U5和U6)，以及组蛋白pre-mRNA 3'端形成所需的U7。除了先前鉴定的核仁抗原外，我们还展示了针对Sm表位、三甲基鸟苷和coilin的抗体染色。由于这些前核仁体的组成更接近于盘绕体而不是核仁，我们建议将它们称为盘绕体。在转录不活跃的原核中存在大卷曲体，这表明它们可能在RNA加工组分的进口、组装和储存中发挥作用，但它们本身不是加工位点。在转录活跃的细胞核中，卷体可以作为snRNP复合物的初始预组装和分布位点，参与三种主要的RNA加工途径：pre-mRNA剪接、pre-rRNA加工和组蛋白pre-mRNA 3'端形成。
When demembranated sperm nuclei are placed in a Xenopus egg extract, they become surrounded by a nuclear envelope and then swell to form morphologically typical pronuclei. Granules ranging from < 1.0 to similar to 3.0 mu m in diameter appear within such nuclei. Bell et al. identified four nucleolar proteins in these ''prenucleolar bodies'' by immunofluorescent staining (fibrillarin, nucleolin, B23/NO38, 180-kDa nucleolar protein). By in situ hybridization we show that these bodies also contain U3 and U8 small nuclear RNAs (snRNAs), known to be involved in pre-rRNA processing. Moreover, they contain all the snRNAs involved in pre-mRNA splicing (U1, U2, U4, U5, and U6), as well as U7, which is required for histone pre-mRNA 3' end formation. In addition to the nucleolar antigens previously identified, we demonstrated staining with antibodies against the Sm epitope, trimethylguanosine, and coilin. Because the composition of these prenucleolar bodies is closer to that of coiled bodies than to nucleoli, we propose that they be referred to as coiled bodies. The existence of large coiled bodies in transcriptionally inactive pronuclei suggests that they may play a role in the import, assembly, and storage of RNA processing components but are not themselves sites of processing. In transcriptionally active nuclei coiled bodies could serve as sites for initial preassembly and distribution of snRNP complexes for the three major RNA processing pathways: pre-mRNA splicing, pre-rRNA processing, and histone pre-mRNA 3' end formation.