Nucleolin modulates the subcellular localization of GDNF-inducible zinc finger protein 1 and its roles in transcription and cell proliferation
Nucleolin modulates the subcellular localization of GDNF-inducible zinc finger protein 1 and its roles in transcription and cell proliferation
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DOI：
10.1016/j.yexcr.2007.07.003
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发表时间：
2007-10-15
影响因子：
3.7
通讯作者：
Takahashi, Masahide
中科院分区：
文献类型：
--
作者：
Dambara, Atsushi;Morinaga, Takatoshi;Takahashi, Masahide
GZF1是胶质细胞源性神经营养因子(GDNF)诱导的锌指蛋白。它是一种序列特异性转录抑制因子，含有一个BTB/POZ结构域(BTB/POZ)和十个锌指基序。在本研究中，我们使用免疫沉淀和质谱仪来鉴定核仁素是一种GZF1结合蛋白。缺失分析表明，GZF1的锌指基序1-4介导了其与核仁素的结合。当GZF1中锌指1-4缺失或核仁表达被短干扰RNA(SiRNA)抑制时，GZF1的核定位受到损害。这些结果表明，核仁素参与了GZF1的适当亚细胞分布。此外，核仁蛋白的过度表达适度抑制了GZF1的转录抑制活性，而siRNA下调核仁蛋白的表达则增强了其活性。因此，GZF1的抑制活性受核仁素表达水平的调节。最后，我们发现GZF1基因的敲除和核仁素的表达显著地损害了细胞的增殖。这些发现表明，GZF1的生理功能可能受该蛋白与核仁素的相互作用的调节。(C)2007 Elsevier Inc.保留所有权利。
GZF1 is a zinc finger protein induced by glial cell-line-derived neurotrophic factor (GDNF). It is a sequence-specific transcriptional repressor with a BTB/POZ (Broad complex, Tramtrack, Bric a brac/Poxvirus and zinc finger) domain and ten zinc finger motifs. In the present study, we used immunoprecipitation and mass spectrometry to identify nucleolin as a GZF1-binding protein. Deletion analysis revealed that zinc finger motifs 1-4 of GZF1 mediate its association with nucleolin. When zinc fingers 1-4 were deleted from GZF1 or nucleolin expression was knocked down by short interference RNA (siRNA), nuclear localization of GZF1 was impaired. These results suggest that nucleolin is involved in the proper subcellular distribution of GZF1. In addition, overexpression of nucleolin moderately inhibited the transcriptional repressive activity of GZF1 whereas knockdown of nucleolin expression by siRNA enhanced its activity. Thus, the repressive activity of GZF1 is modulated by the level at which nucleolin is expressed. Finally, we found that knockdown of GZF1 and nucleolin expression markedly impaired cell proliferation. These findings suggest that the physiological functions of GZF1 may be regulated by the protein's association with nucleolin. (C) 2007 Elsevier Inc. All rights reserved.