Interactions of CCCH zinc finger proteins with mRNA - Binding of tristetraprolin-related zinc finger proteins to Au-rich elements and destabilization of mRNA
Interactions of CCCH zinc finger proteins with mRNA - Binding of tristetraprolin-related zinc finger proteins to Au-rich elements and destabilization of mRNA
复制标题
DOI：
10.1074/jbc.m001696200
复制
发表时间：
2000-06-09
影响因子：
4.8
通讯作者：
Blackshear, PJ
中科院分区：
文献类型：
--
作者：
Lai, WS;Carballo, E;Blackshear, PJ
由于TNF alpha mRNA的稳定性增加，TTP的稳定性增加而显示出源自肿瘤坏死因子α（TNF Alpha）释放的巨噬细胞（TTP） - 缺陷小鼠的肿瘤坏死因子α（TNF alpha）释放增加，然后显示出可直接与Au-rich区域结合的TNF Alpha mRNA，从而显示出TTP的稳定性。 TTP是哺乳动物和Xenopus中TNFαmRNA的3'-非翻译区域的（IS），TTP是一个由三个已知的锌指蛋白组成的小家族的原型，这些锌指蛋白包含两个CCCH锌指的含量，这些锌指的含量是两个CCCH锌指的分开的18个氨基酸。在爪蟾和鱼类中已经确定了第四个相关的家庭成员。我们在这里表明，所有四个家庭成员的代表都能够与TNF alpha结合，在无细胞系统中，并且在大多数情况下，促进了完整细胞中TNF alpha mRNA的分解。由于这些CCCH蛋白的主要序列在其串联锌指域中最密切相关，因此我们测试了包含两个锌指的TTP的各种片段是否类似于这些分析中的完整蛋白。我们发现，TTP的氨基和羧基末端截断形式以及包含两个锌指的77个氨基酸片段可以与TNFα结合，在无细胞的交联和凝胶移位分析中。另外，这些TTP的截断形式还可以刺激完整细胞中TNF alpha mRNA的明显去苯和/或分解。来自所有四组同源蛋白的串联锌指域的比对已经确定了不变的残基以及大概有助于结合和蛋白质特异性活性的组特异性氨基酸。
Macrophages derived from tristetraprolin (TTP)-deficient mice exhibited increased tumor necrosis factor alpha (TNF alpha) release as a consequence of increased stability of TNF alpha mRNA, TTP was then shown to destabilize TNF alpha mRNA after binding directly to the AU-rich region (ARE) of the 3'-untranslated region of the TNF alpha mRNA In mammals and in Xenopus, TTP is the prototype of a small family of three known zinc finger proteins containing two CCCH zinc fingers spaced 18 amino acids apart; a fourth more distantly related family member has been identified in Xenopus and fish. We show here that representatives of all four family members were able to bind to the TNF alpha ARE in a cell-free system and, in most cases, promote the breakdown of TNF alpha mRNA in intact cells. Because the primary sequences of these CCCH proteins are most closely related in their tandem zinc finger domains, we tested whether various fragments of TTP that contained both zinc fingers resembled the intact protein in these assays. We found that amino- and carboxyl-terminal truncated forms of TTP, as well as a 77 amino acid fragment that contained both zinc fingers, could bind to the TNF alpha ARE in cell-free cross-linking and gel shift assays. In addition, these truncated forms of TTP could also stimulate the apparent deadenylation and/or breakdown of TNF alpha mRNA in intact cells. Alignments of the tandem zinc finger domains from all four groups of homologous proteins have identified invariant residues as well as group-specific signature amino acids that presumably contribute to ARE binding and protein-specific activities, respectively.