The evolutionarily conserved region of the U snRNA export mediator PHAX is a novel RNA-binding domain that is essential for U snRNA export
The evolutionarily conserved region of the U snRNA export mediator PHAX is a novel RNA-binding domain that is essential for U snRNA export
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DOI：
10.1017/s1355838201002278
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发表时间：
2001-03-01
期刊：
影响因子：
4.5
通讯作者：
Ohno, M
中科院分区：
文献类型：
--
作者：
Segref, A;Mattaj, IW;Ohno, M
在后生动物中，剪接体 U snRNA 的一个子集在转录后从细胞核中输出。这种输出发生在包含 U snRNA、核帽结合复合物 (CBC)、富含亮氨酸的核输出信号受体 CRM1/Xpo1、RanGTP 和最近鉴定的磷蛋白 PHAX（(ph) over bar osphorylated (a) over bar adaptor for RNA e (x) over bar port）的大型复合物中，先前的结果表明 PHAX 与 U snRNA 输出复合物中的 RNA、CBC 和 Xpo1 直接接触，我们现在已进行对 PHAX 功能域的系统表征，PHAX 进化上最保守的区域被证明是一个新的 RNA 结合域，对于 U snRNA 输出至关重要。此外，PHAX 包含两个主要的核定位信号 (NLS)，这是其在输出后再循环到细胞核所需的。PHAX 与 CBC 的相互作用结构域至少部分不同于 RNA 结合结构域和 NLS。因此，PHAX 的不同相互作用域使其能够充当 U snRNA 输出复合物组装的支架。
In metazoa, a subset of spliceosomal U snRNAs are exported from the nucleus after transcription. This export occurs in a large complex containing a U snRNA, the nuclear cap binding complex (CBC), the leucine-rich nuclear export signal receptor CRM1/Xpo1, RanGTP, and the recently identified phosphoprotein PHAX ((ph) over bar osphorylated (a) over bar daptor for RNA e (x) over bar port), Previous results indicated that PHAX made direct contact with RNA, CBC,and Xpo1 in the U snRNA export complex, We have now performed a systematic characterization of the functional domains of PHAX, The most evolutionarily conserved region of PHAX is shown to be a novel RNA-binding domain that is essential for U snRNA export. In addition, PHAX contains two major nuclear localization signals (NLSs) that are required for its recycling to the nucleus after export, The interaction domain of PHAX with CBC is at least partly distinct from the RNA-binding domain and the NLSs. Thus, the different interaction domains of PHAX allow it to act as a scaffold for the assembly of U snRNA export complexes.