Molecular cloning and functional characterization of mouse Nxf family gene products
Molecular cloning and functional characterization of mouse Nxf family gene products
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DOI：
10.1016/j.ygeno.2005.01.003
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发表时间：
2005-05-01
期刊：
影响因子：
4.4
通讯作者：
Yoneda, Y
中科院分区：
文献类型：
--
作者：
Sasaki, M;Takeda, E;Yoneda, Y
Tap 是进化上保守的核 RNA 输出因子 (NXF) 蛋白家族的成员，与大量聚 (A)(+) RNA 的核输出有关。制备了编码小鼠 NXF 蛋白（Tap、NXF7、NXF2 和 NXF3）的 cDNA，并根据基因组组织、表达模式和生化特性对基因产物进行了表征。发现 Mouse Tap 普遍表达，而观察到小鼠 Nxf2、Nxf3 和 Nxf7 的组织和发育阶段特异性表达。尽管小鼠 Tap 和 NXF2 与核孔蛋白的苯丙氨酸-甘氨酸重复序列结合，但 NXF7 和 NXF3 却没有。 GFP 标记的小鼠 Tap 和 NXF2 主要位于细胞核中。相比之下，带有 GFP 标记的 NXF7 和 NXF3 只位于细胞质中。正如人类对应物所示，破坏富含亮氨酸的核输出信号或瘦霉素 B 处理会消除小鼠 NXF3 的细胞质定位。 p15/NXT1 是人 Tap 在 mRNA 输出中的重要辅助因子，能够与小鼠 Tap、NXF2 和 NXF3 结合，但 NXF7 不能形成稳定的异二聚体复合物。瞬时转染实验表明，只有小鼠 Tap 和 NXF2 才能增强低效输出 mRNA 底物的核输出。根据这些数据讨论了人和小鼠 Nxf 基因之间的直系同源关系。 (c) 2005 Elsevier Inc. 保留所有权利。
Tap, a member of the evolutionarily conserved nuclear RNA export factor (NXF) family of proteins, has been implicated in the nuclear export of bulk poly(A)(+) RNAs. cDNAs encoding the mouse NXF proteins (Tap, NXF7, NXF2, and NXF3) were prepared, and the gene products were characterized in terms of their genomic organization, expression patterns, and biochemical properties. Mouse Tap was found to be ubiquitously expressed, whereas tissue- and developmental stage specific expression of mouse Nxf2, Nxf3, and Nxf7 was observed. Although mouse Tap and NXF2 bound to the phenylalanine-glycine repeat sequences of nucleoporins, NXF7 and NXF3 did not. GFP-tagged mouse Tap and NXF2 were localized predominantly in the nucleus. In contrast, GFP-tagged NXF7 and NXF3 were localized exclusively in the cytoplasm. As shown for the human counterpart, disruption of the leucine-rich nuclear export signal or leptomycin B treatment abolishes the cytoplasmic localization of mouse NXF3. p15/NXT1, an essential cofactor for human Tap in the export of mRNAs, was able to bind to mouse Tap, NXF2, and NXF3, but NXF7 did not form a stable heterodimeric complex. Transient transfection experiments indicated that only mouse Tap and NXF2 enhance the nuclear export of an otherwise inefficiently exported mRNA substrate. The orthologous relationship between human and mouse Nxf genes is discussed on the basis of these data. (c) 2005 Elsevier Inc. All rights reserved.