Coilin Is Essential for Cajal Body Organization in Drosophila melanogaster
Coilin Is Essential for Cajal Body Organization in Drosophila melanogaster
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DOI：
10.1091/mbc.e08-05-0525
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发表时间：
2009-03-15
影响因子：
3.3
通讯作者：
Gall, Joseph G.
中科院分区：
文献类型：
--
作者：
Liu, Ji-Long;Wu, Zheng'an;Gall, Joseph G.
卡哈尔小体（Cajal bodies，CB）是存在于脊椎动物、昆虫和植物等多种生物体中的核细胞器。它们最常通过抗标记蛋白卷曲蛋白的抗体来鉴定。由于卷曲蛋白的氨基酸序列在进化上不是很保守，所以通过同源性搜索很难识别卷曲蛋白的直向同源物。在这里，我们报告的鉴定果蝇coilin和描述其分布在组织中的苍蝇。令人惊讶的是，我们发现卷曲蛋白不仅在CB中，而且在组蛋白基因座体（HLBs）中，使用卷曲蛋白作为CB的唯一标记提出了疑问。我们分析了卷曲蛋白基因中的两个无效突变体和一个piggyBac插入突变体，这导致卷曲蛋白从种系中特异性丢失。所有三个突变体都是纯合的，能活的，能育的。缺乏卷曲蛋白的细胞也缺乏其他CB标志物的明显病灶，包括原纤维蛋白、运动神经元存活（SMN）蛋白、U2小核RNA（snRNA）、U5 snRNA和小CB特异性（sca）RNA U85。然而，在线圈蛋白无效的苍蝇中，HLBs没有明显的影响。因此，卷曲蛋白是果蝇正常CB组织所必需的，但对功能配子的生存力或产生不是必需的。
Cajal bodies (CBs) are nuclear organelles that occur in a variety of organisms, including vertebrates, insects, and plants. They are most often identified with antibodies against the marker protein coilin. Because the amino acid sequence of coilin is not strongly conserved evolutionarily, coilin orthologues have been difficult to recognize by homology search. Here, we report the identification of Drosophila melanogaster coilin and describe its distribution in tissues of the fly. Surprisingly, we found coilin not only in CBs but also in histone locus bodies (HLBs), calling into question the use of coilin as an exclusive marker for CBs. We analyzed two null mutants in the coilin gene and a piggyBac insertion mutant, which leads to specific loss of coilin from the germline. All three mutants are homozygous viable and fertile. Cells that lack coilin also lack distinct foci of other CB markers, including fibrillarin, the survival motor neuron (SMN) protein, U2 small nuclear RNA (snRNA), U5 snRNA, and the small CB-specific (sca) RNA U85. However, HLBs are not obviously affected in coilin-null flies. Thus, coilin is required for normal CB organization in Drosophila but is not essential for viability or production of functional gametes.