SR proteins preferentially associate with mRNAs in the nucleus and facilitate their export to the cytoplasm
SR proteins preferentially associate with mRNAs in the nucleus and facilitate their export to the cytoplasm
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DOI：
10.1111/j.1365-2443.2004.00774.x
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发表时间：
2004-10-01
期刊：
影响因子：
2.1
通讯作者：
Ohno, M
中科院分区：
文献类型：
--
作者：
Masuyama, K;Taniguchi, I;Ohno, M
不同种类的RNA通过不同的机制输出到细胞质。每一类RNA在输出到细胞质之前都与核蛋白形成不同的复合物。为了获得与细胞核中mrna特异性相关的蛋白因子的全面信息，我们将各种rna显微注射到爪蟾卵母细胞细胞核后进行了体内紫外交联分析。我们发现一组蛋白质优先与mrna交联。免疫沉淀实验显示，一些交联信号与SR（丝氨酸/精氨酸丰富）蛋白相对应，SR（丝氨酸/精氨酸丰富）蛋白是参与pre-mRNA剪接的重要rna结合蛋白家族。以前有人认为SR蛋白家族的一些成员参与了特定的无内含子mRNA、组蛋白H2A mRNA和一些剪接mRNA的输出。然而，SR蛋白是否参与一般mrna的输出，特别是不含特异性RNA输出元件的一般无内含子mrna的输出，尚不清楚。当我们将一种针对SR蛋白的抗体微注射到细胞核中时，无论mrna是否通过pre-mRNA剪接产生，mrna的输出都受到严重抑制，而其他rna的输出则不受影响。这些结果明确表明SR蛋白参与了一般无内含子mrna和剪接mrna的输出。
Different classes of RNA are exported to the cytoplasm by distinct mechanisms. Each class of RNA forms distinct complexes with nuclear proteins prior to its export to the cytoplasm. In our attempt to obtain comprehensive information of protein factors that specifically associate with mRNAs in the nucleus, we performed in vivo UV-crosslinking analysis after microinjection of various RNAs into Xenopus oocyte nucleus. We found a group of proteins preferentially crosslinked to mRNAs. Immunoprecipitation experiments revealed that some of the crosslinked signals corresponded to SR (serine/arginine-rich) proteins, a family of essential RNA-binding proteins involved in pre-mRNA splicing. It was previously suggested that some members of SR protein family are involved in export of a specific intronless mRNA, histone H2A mRNA and some spliced mRNAs. However, it is still to be clarified if SR proteins are involved in export of general mRNAs, especially general intronless mRNAs that do not contain specific RNA export elements. When we microinjected an antibody against SR proteins into the nucleus, export of mRNAs was severely inhibited, regardless of whether the mRNAs were produced via pre-mRNA splicing or not, whereas export of other RNAs was not affected. These results unequivocally showed that SR proteins are involved in export of both general intronless and spliced mRNAs.