Rna Transport

Abstract

RNA molecules synthesized in the nucleus are transported to their sites of function throughout the eukaryotic cell by specific transport pathways. This review focuses on transport of messenger RNA, small nuclear RNA, ribosomal RNA, and transfer RNA between the nucleus and the cytoplasm. The general molecular mechanisms involved in nucleocytoplasmic transport of RNA are only beginning to be understood. However, during the past few years, substantial progress has been made. A major theme that emerges from recent studies of RNA transport is that specific signals mediate the transport of each class of RNA, and these signals are provided largely by the specific proteins with which each RNA is associated.

Tumor‐specific exon creation of the HELLS/SMARCA6 gene in non‐small cell lung cancer

“…The hnRNP A2 and B1 genes have been reported to be involved in RNA splicing and transport 34,35 and are associated with human lung cancer. 36 Therefore, we analyzed the ratio of hnRNP A2 to hnRNP B1 gene expression in NSCLC.…”

“…No mutation was detected in the exon-intron boundary and intron 3. Furthermore, we analyzed expression of the hnRNP A2 and B1 genes in NSCLC tissues by RT-PCR as associations have been reported between the expression ratio of the hnRNP A2/B1 genes and RNA splicing error 34,35 and between elevated hnRNP B1 mRNA level and human lung cancer. 36 However, expression of hnRNP A2 and B1 was detected at similar levels in tumor samples with and without variant 1, and no remarkable differences of expression were detected between tumor and normal tissues (data not shown).…”

β-Catenin Can Be Transported into the Nucleus in a Ran-unassisted Manner

“…A number of recent discoveries have led to the development of a model for receptor-mediated active nuclear import and export (for reviews, see Corbett and Silver, 1997;Gö rlich, 1997;Nakielny et al, 1997;Nigg, 1997;Ullman et al, 1997;Imamoto et al, 1998;Mattaj and Englmeier, 1998;Ohno et al, 1998). The model involves two essential elements, which are required for both the import and export pathways: 1) soluble transport factors, which recognize respective signals present in each protein, which is either imported into or exported out of the nucleus; and 2) a small GTPase Ran that affects the affinity between the transport factors and signals by binding directly to the transport factors.…”

“…The NPC is a large proteinaceous structure of ϳ125 MDa in size and mediates bidirectional transport via several different mechanisms (for reviews, see Davis, 1995;Fabre and Hurt, 1997). Small molecules, such as ions, low-molecular-weight metabolites, and proteins smaller than 20 -40 kDa cross 10-nm-diameter aqueous channels of the NPC by passive diffusion, whereas larger molecules are generally transported through the gated channels of the NPC via an active, receptor-mediated mechanism.A number of recent discoveries have led to the development of a model for receptor-mediated active nuclear import and export (for reviews, see Corbett and Silver, 1997;Gö rlich, 1997;Nakielny et al, 1997;Nigg, 1997;Ullman et al, 1997;Imamoto et al, 1998;Mattaj and Englmeier, 1998;Ohno et al, 1998). The model involves two essential elements, which are required for both the import and export pathways: 1) soluble transport factors, which recognize respective signals present in each protein, which is either imported into or exported out of the nucleus; and 2) a small GTPase Ran that affects the affinity between the transport factors and signals by binding directly to the transport factors.…”

Rev-ing up post-transcriptional HIV-1 RNA expression

“…A simple view of how HIV-1 solves this challenge is that it encodes a viral "export" protein that recognizes a cis-viral-RNA motif contained in unspliced/partially spliced viral transcripts. [9][10][11] Thus, the HIV-1 Rev protein serves to export from the nucleus into the cytoplasm unspliced/partially spliced genomic, Gag, Pol, Env RNAs that contain a cis-RRE (Rev-responsive element) motif. 12 The simple picture of Rev-RRE interaction belies a more complex process that involves many host cell co-factors.…”