Molecular cloning and characterization of Nop25, a novel nucleolar RNA binding protein, highly conserved in vertebrate species
Molecular cloning and characterization of Nop25, a novel nucleolar RNA binding protein, highly conserved in vertebrate species
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DOI：
10.1016/j.yexcr.2005.12.017
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发表时间：
2006-04-15
影响因子：
3.7
通讯作者：
Tanaka, J
中科院分区：
文献类型：
--
作者：
Suzuki, S;Kanno, M;Tanaka, J
我们在这里报告的识别和表征的一种新的核仁RNA结合蛋白，称为Nop 25的基础上，其预测的分子大小和亚细胞位置。Nop 25的同源物作为假设蛋白广泛存在于多种脊椎动物中，但在酵母、植物和原核生物中未发现。Nop 25在成年小鼠器官中广泛表达，并在小鼠胚胎发育过程中组成型表达。用抗Nop 25抗体的间接免疫荧光分析以及使用GFP融合蛋白的实验证明Nop 25定位于核仁中。用低剂量的放线菌素D处理细胞导致Nop 25易位到核仁的外围，这表明Nop 25的核仁定位与rRNA转录相关。用RNase A处理COS 7细胞导致Nop 25从核仁中完全解离，而体外结合试验证明Nop 25可以直接与单链核酸结合。进一步用免疫沉淀法对Nop 25的相关RNA分子进行了鉴定，结果表明Nop 25可能与28 S rRNA结合。对这种新的核仁RNA结合蛋白的研究可能会提供新的信息，复杂的核仁机制有关的转录和加工的rRNA分子和/或随后的装配和成熟的核糖体。(c)2005年爱思唯尔公司All rights reserved.
We report here the identification and characterization of a novel nucleolar RNA binding protein, referred to as Nop25 as based on its predicted molecular size and subcellular location. Nop25 homologues were widely discovered in diverse vertebrate species as hypothetical proteins, but not found in yeasts, plants and prokaryotic organisms. Nop25 was ubiquitously expressed in adult mouse organs and constitutively during mouse embryogenesis. indirect immunofluorescence analysis with an anti-Nop25 antibody, as well as an experiment using a GFP-fused protein, demonstrated that Nop25 was localized in the nucleolus. Treatment of the cells with a low doses of actinomycin D caused Nop25 to translocate to the periphery of the nucleolus, suggesting that nucleolar localization of Nop25 is associated with rRNA transcription. Treatment of COS7 cells with RNase A resulted in a complete dissociation of Nop25 from the nucleolus, while in vitro binding assay demonstrated that Nop25 could bind directly to single-stranded nucleic acids. Further characterization of associated RNA molecules with Nop25 using immunoprecipitation experiment showed that Nop25 might bind to 28S rRNA. Studies on this novel nucleolar RNA binding protein may provide new information on the intricate nucleolar machinery as related to the transcription and processing of rRNA molecules and/or the subsequent assembly and maturation of ribosomes. (c) 2005 Elsevier Inc. All rights reserved.