Schütz Sylvia, Chemnitz Jan, Spillner Christiane, Frohme Marcus, Hauber Joachim, Kehlenbach Ralph H
University of Heidelberg, Department of Virology, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
J Mol Biol. 2006 May 12;358(4):997-1009. doi: 10.1016/j.jmb.2006.02.041. Epub 2006 Mar 3.
In metazoans, the nuclear export of bulk mRNAs is mediated by the export receptor TAP, together with its binding partner p15. A number of viral mRNAs, including the unspliced and partially spliced mRNA species of the human immunodeficiency virus (HIV), however, use an alternative export route via the importin beta-related export receptor CRM1. This raises the question of whether a subset of cellular mRNAs might be exported by CRM1 as well. To identify such mRNAs, we performed a systematic screen in different cell lines, using representational difference analyses of cDNA (cDNA-RDA). In HeLa and Cl-4 cells no cellular transcripts could be identified as exported via CRM1. In contrast, we found a number of CRM1-dependent mRNAs in Jurkat T cells, most of which are induced during a T cell response. One of the identified gene products, the dendritic cell marker CD83, was analyzed in detail. CD83 expression depends on a functional CRM1 pathway in activated Jurkat T cells as well as in a heterologous expression system, independent of activation. Our results point to an important role of the CRM1-dependent export pathway for the expression of CD83 and other genes under conditions of T cell activation.
在后生动物中，大量mRNA的核输出由输出受体TAP及其结合伴侣p15介导。然而，许多病毒mRNA，包括人类免疫缺陷病毒（HIV）的未剪接和部分剪接的mRNA种类，通过与输入蛋白β相关的输出受体CRM1使用替代输出途径。这就提出了一个问题，即细胞mRNA的一个子集是否也可能由CRM1输出。为了鉴定此类mRNA，我们在不同细胞系中进行了系统筛选，使用cDNA代表性差异分析（cDNA-RDA）。在HeLa和Cl-4细胞中，未发现可通过CRM1输出的细胞转录本。相反，我们在Jurkat T细胞中发现了许多依赖CRM1的mRNA，其中大多数在T细胞应答过程中被诱导。对其中一个鉴定出的基因产物，即树突状细胞标志物CD83，进行了详细分析。CD83的表达在活化的Jurkat T细胞以及异源表达系统中均依赖于功能性CRM1途径，且与活化无关。我们的结果表明，在T细胞活化条件下，依赖CRM1的输出途径对CD83和其他基因的表达具有重要作用。
