EVIDENCE THAT HIV-1 REV DIRECTLY PROMOTES THE NUCLEAR EXPORT OF UNSPLICED RNA
EVIDENCE THAT HIV-1 REV DIRECTLY PROMOTES THE NUCLEAR EXPORT OF UNSPLICED RNA
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DOI：
10.1002/j.1460-2075.1994.tb06728.x
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发表时间：
1994-09-01
期刊：
影响因子：
11.4
通讯作者：
RAUTMANN, G
中科院分区：
文献类型：
--
作者：
FISCHER, U;MEYER, S;RAUTMANN, G
人类免疫缺陷病毒1型（HIV-1）的Rev反式激活因子是一种蛋白质，通过识别被称为Rev应答元件（RRE）的靶序列，调节来自相同病毒转录物的剪接和未剪接形式的病毒mrna在细胞质中同时出现。Rev是直接作用于RNA输出还是通过抑制剪接，或者两者兼而有之，仍然是一个有争议的问题。我们在非洲爪蟾卵母细胞中通过将含有RRE的RNA分子与纯化的重组Rev蛋白一起微注射到卵母细胞核中来解决这个问题。在内含子中含有RRE的腺病毒前mrna在没有Rev蛋白和存在Rev蛋白的情况下都能很好地剪接。只有在Rev存在的情况下，未剪接的pre-mRNA才会从细胞核中输出；更令人惊讶的是，切除的内含子（含RRE）也被输出。此外，缺乏内含子序列的含有rre的mRNA分子也以rev依赖的方式有效地从细胞核中输出。因此，我们的研究结果表明，Rev可以直接作用于核输出水平，而不依赖于它可能对pre-mRNA剪接施加的任何抑制作用。最后，我们发现Rev突变体M10，先前在人类淋巴样细胞中被证明是无活性的，也不能从卵母细胞核中输出含有rre的RNA分子，这表明在人类和非洲爪蟾之间进化上保守的一种或多种细胞因子在两种细胞系统中与Rev相互作用，促进核RNA输出。
The Rev trans-activator of human immmunodeficiency virus type 1 (HIV-1) is a protein that regulates the simultaneous appearance in the cytoplasm of both spliced and unspliced forms of viral mRNAs from the same viral transcripts by way of recognition of a target sequence termed the Rev-responsive element (RRE). Whether Rev acts directly on RNA export or by inhibition of splicing, or both, is still a matter of debate. We have addressed this issue in Xenopus laevis oocytes by microinjecting RNA molecules containing RRE along with purified recombinant Rev protein into the oocyte nuclei. Adenovirus pre-mRNA containing an RRE in the intron was spliced equally well in the absence and presence of Rev protein. Only in the presence of Rev was non-spliced pre-mRNA exported from the nucleus; more surprisingly, the excised intron lariat (containing RRE) was also exported. Furthermore, an RRE-containing mRNA molecule that lacked intron sequences was also efficiently exported from the nucleus in a Rev-dependent manner. Therefore our results demonstrate that Rev can act directly at the level of nuclear export, independent of any inhibitory effect that it may exert on the splicing of pre-mRNA. Finally, our finding that the Rev mutant M10, shown previously to be inactive in human lymphoid cells, was also unable to export RRE-containing RNA molecules from oocyte nuclei suggests that one or more cellular factors, evolutionarily conserved between humans and Xenopus, interact with Rev in both cell systems to promote nuclear RNA export.