Neville M, Stutz F, Lee L, Davis L I, Rosbash M
Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02254, USA.
Curr Biol. 1997 Oct 1;7(10):767-75. doi: 10.1016/s0960-9822(06)00335-6.
The human immunodeficiency virus (HIV-1) uses the viral protein Rev to regulate gene expression by promoting the export of unspliced and partially spliced viral transcripts. Rev has been shown to function in a variety of organisms, including Saccharomyces cerevisiae. The export activity of Rev depends on a nuclear export signal (NES), which is believed to interact either directly or indirectly with the nuclear pore complex to carry out its export function. Crm1p is a member of the importin-beta protein family, other members of which are known to be directly involved in nuclear import. Crm1p has recently been shown to contribute to nuclear export in vertebrate systems. Here, we have studied this mechanism of nuclear to cytoplasmic transport.
Viable mis-sense mutations in the CRM1 gene substantially reduced or eliminated the biological activity of Rev in S. cerevisiae, providing strong evidence that Crm1p also contributes to transport of Rev NES-containing proteins and ribonucleoproteins in this organism. Crm1p interacted with FG-repeat-containing nuclear pore proteins as well as Rev, and we have demonstrated that the previously described two-hybrid interaction between Rev and the yeast nuclear pore protein Rip1p is dependent on wild-type Crm1p.
We conclude that Crm1p interacts with the Rev NES and nuclear pore proteins during delivery of cargo to the nuclear pore complex. Our findings also agree well with current experiments on Crm1p orthologs in Schizosaccharomyces pombe and in vertebrate systems.
人类免疫缺陷病毒1型（HIV-1）利用病毒蛋白Rev通过促进未剪接和部分剪接的病毒转录本的输出，来调控基因表达。Rev已被证明在包括酿酒酵母在内的多种生物体中发挥作用。Rev的输出活性依赖于一个核输出信号（NES），该信号被认为直接或间接与核孔复合体相互作用以执行其输出功能。Crm1p是输入蛋白β家族的成员，该家族的其他成员已知直接参与核输入。最近已表明Crm1p在脊椎动物系统中有助于核输出。在此，我们研究了这种从核到细胞质的转运机制。
CRM1基因中的可行错义突变显著降低或消除了Rev在酿酒酵母中的生物学活性，这有力地证明了Crm1p在该生物体中也有助于含Rev NES的蛋白质和核糖核蛋白的转运。Crm1p与含FG重复序列的核孔蛋白以及Rev相互作用，并且我们已证明先前描述的Rev与酵母核孔蛋白Rip1p之间的双杂交相互作用依赖于野生型Crm1p。
我们得出结论，在将货物递送至核孔复合体的过程中，Crm1p与Rev NES和核孔蛋白相互作用。我们的发现也与目前关于粟酒裂殖酵母和脊椎动物系统中Crm1p直系同源物的实验结果非常吻合。
