scholarly journals The Interaction between Cap-binding Complex and RNA Export Factor Is Required for Intronless mRNA Export

2007 ◽  
Vol 282 (21) ◽  
pp. 15645-15651 ◽  
Author(s):  
Takayuki Nojima ◽  
Tetsuro Hirose ◽  
Hiroshi Kimura ◽  
Masatoshi Hagiwara
Keyword(s):  
Mrna Export ◽  
Cap Binding Complex ◽  
Rna Export

scholarly journals Roles for RNA export factor, Nxt1, in ensuring muscle integrity and normal RNA expression in Drosophila

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kevin van der Graaf ◽  
Katia Jindrich ◽  
Robert Mitchell ◽  
Helen White-Cooper
Keyword(s):  
Mrna Export ◽  
Rna Stability ◽  
Muscle Degeneration ◽  
Loss Of Function ◽  
Cellular Functions ◽  
Partial Loss ◽  
Export Pathway ◽  
Pathway Gene ◽  
Rna Export

Abstract The mRNA export pathway is responsible for the transport of mRNAs from the nucleus to the cytoplasm, and thus is essential for protein production and normal cellular functions. A partial loss of function allele of the mRNA export factor Nxt1 in Drosophila shows reduced viability and sterility. A previous study has shown that the male fertility defect is due to a defect in transcription and RNA stability, indicating the potential for this pathway to be implicated in processes beyond the known mRNA transport function. Here we investigate the reduced viability of Nxt1 partial loss of function mutants, and describe a defect in growth and maintenance of the larval muscles, leading to muscle degeneration. RNA-seq revealed reduced expression of a set of mRNAs, particularly from genes with long introns in Nxt1 mutant carcass. We detected differential expression of circRNA, and significantly fewer distinct circRNAs expressed in the mutants. Despite the widespread defects in gene expression, muscle degeneration was rescued by increased expression of the costamere component tn (abba) in muscles. This is the first report of a role for the RNA export pathway gene Nxt1 in the maintenance of muscle integrity. Our data also links the mRNA export pathway to a specific role in the expression of mRNA and circRNA from common precursor genes, in vivo.

scholarly journals TAP (NXF1) Belongs to a Multigene Family of Putative RNA Export Factors with a Conserved Modular Architecture

2000 ◽  
Vol 20 (23) ◽  
pp. 8996-9008 ◽  
Author(s):  
Andrea Herold ◽  
Mikita Suyama ◽  
João P. Rodrigues ◽  
Isabelle C. Braun ◽  
Ulrike Kutay ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Rna Binding ◽  
Mrna Export ◽  
Modular Architecture ◽  
Export Activity ◽  
Evolutionarily Conserved ◽  
Rna Export ◽  
Higher Eukaryotes ◽  
Leucine Rich Repeats ◽  
Rna Export Factors

ABSTRACT Vertebrate TAP (also called NXF1) and its yeast orthologue, Mex67p, have been implicated in the export of mRNAs from the nucleus. The TAP protein includes a noncanonical RNP-type RNA binding domain, four leucine-rich repeats, an NTF2-like domain that allows heterodimerization with p15 (also called NXT1), and a ubiquitin-associated domain that mediates the interaction with nucleoporins. Here we show that TAP belongs to an evolutionarily conserved family of proteins that has more than one member in higher eukaryotes. Not only the overall domain organization but also residues important for p15 and nucleoporin interaction are conserved in most family members. We characterize two of four human TAP homologues and show that one of them, NXF2, binds RNA, localizes to the nuclear envelope, and exhibits RNA export activity. NXF3, which does not bind RNA or localize to the nuclear rim, has no RNA export activity. Database searches revealed that although only one p15(nxt) gene is present in the Drosophila melanogaster and Caenorhabditis elegans genomes, there is at least one additional p15 homologue (p15-2 [also called NXT2]) encoded by the human genome. Both human p15 homologues bind TAP, NXF2, and NXF3. Together, our results indicate that the TAP-p15 mRNA export pathway has diversified in higher eukaryotes compared to yeast, perhaps reflecting a greater substrate complexity.

scholarly journals mRNA export through an additional cap-binding complex consisting of NCBP1 and NCBP3

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Anna Gebhardt ◽  
Matthias Habjan ◽  
Christian Benda ◽  
Arno Meiler ◽  
Darya A. Haas ◽  
...  
Keyword(s):  
Mrna Export ◽  
Cap Binding Complex

scholarly journals The prototype γ-2 herpesvirus nucleocytoplasmic shuttling protein, ORF 57, transports viral RNA through the cellular mRNA export pathway

2005 ◽  
Vol 387 (2) ◽  
pp. 295-308 ◽  
Author(s):  
Ben J. L. WILLIAMS ◽  
James R. BOYNE ◽  
Delyth J. GOODWIN ◽  
Louise ROADEN ◽  
Guillaume M. HAUTBERGUE ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Mammalian Cells ◽  
Mrna Export ◽  
Dominant Negative ◽  
Viral Rna ◽  
Exon Junction Complex ◽  
Independent Manner ◽  
Exon Junction ◽  
Export Pathway ◽  
Rna Export

HVS (herpesvirus saimiri) is the prototype γ-2 herpesvirus. This is a subfamily of herpesviruses gaining importance since the identification of the first human γ-2 herpesvirus, Kaposi's sarcoma-associated herpesvirus. The HVS ORF 57 (open reading frame 57) protein is a multifunctional transregulatory protein homologous with genes identified in all classes of herpesviruses. Recent work has demonstrated that ORF 57 has the ability to bind viral RNA, shuttles between the nucleus and cytoplasm and promotes the nuclear export of viral transcripts. In the present study, we show that ORF 57 shuttles between the nucleus and cytoplasm in a CRM-1 (chromosomal region maintenance 1)-independent manner. ORF 57 interacts with the mRNA export factor REF (RNA export factor) and two other components of the exon junction complex, Y14 and Magoh. The association of ORF 57 with REF stimulates recruitment of the cellular mRNA export factor TAP (Tip-associated protein), and HVS infection triggers the relocalization of REF and TAP from the nuclear speckles to several large clumps within the cell. Using a dominant-negative form of TAP and RNA interference to deplete TAP, we show that it is essential for bulk mRNA export in mammalian cells and is required for ORF 57-mediated viral RNA export. Furthermore, we show that the disruption of TAP reduces viral replication. These results indicate that HVS utilizes ORF 57 to recruit components of the exon junction complex and subsequently TAP to promote viral RNA export through the cellular mRNA export pathway.

scholarly journals Sem1 is a functional component of the nuclear pore complex–associated messenger RNA export machinery

2009 ◽  
Vol 184 (6) ◽  
pp. 833-846 ◽  
Author(s):  
Marius Boulos Faza ◽  
Stefan Kemmler ◽  
Sonia Jimeno ◽  
Cristina González-Aguilera ◽  
Andrés Aguilera ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Messenger Rna ◽  
Mammalian Cells ◽  
Genome Instability ◽  
Protein Complexes ◽  
Mrna Export ◽  
Nuclear Pore ◽  
Multiple Protein ◽  
Rna Export ◽  
Biochemical Analyses

The evolutionarily conserved protein Sem1/Dss1 is a subunit of the regulatory particle (RP) of the proteasome, and, in mammalian cells, binds the tumor suppressor protein BRCA2. Here, we describe a new function for yeast Sem1. We show that sem1 mutants are impaired in messenger RNA (mRNA) export and transcription elongation, and induce strong transcription-associated hyper-recombination phenotypes. Importantly, Sem1, independent of the RP, is functionally linked to the mRNA export pathway. Biochemical analyses revealed that, in addition to the RP, Sem1 coenriches with components of two other multisubunit complexes: the nuclear pore complex (NPC)-associated TREX-2 complex that is required for transcription-coupled mRNA export, and the COP9 signalosome, which is involved in deneddylation. Notably, targeting of Thp1, a TREX-2 component, to the NPC is perturbed in a sem1 mutant. These findings reveal an unexpected nonproteasomal function of Sem1 in mRNA export and in prevention of transcription-associated genome instability. Thus, Sem1 is a versatile protein that might stabilize multiple protein complexes involved in diverse pathways.

scholarly journals Distinct Functions of the Cap-Binding Complex in Stimulation of Nuclear mRNA Export

2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Rwik Sen ◽  
Priyanka Barman ◽  
Amala Kaja ◽  
Jannatul Ferdoush ◽  
Shweta Lahudkar ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Level ◽  
Mrna Export ◽  
Mrna Splicing ◽  
Content Type ◽  
Cap Binding Complex ◽  
Cleavage And Polyadenylation ◽  
Nascent Mrna ◽  
Stimulation Of ◽  
Active Genes

ABSTRACTCap-binding complex (CBC) associates cotranscriptionally with the cap structure at the 5′ end of nascent mRNA to protect it from exonucleolytic degradation. Here, we show that CBC promotes the targeting of an mRNA export adaptor, Yra1 (forming transcription export [TREX] complex with THO and Sub2), to the active genes and enhances mRNA export inSaccharomyces cerevisiae. Likewise, recruitment of Npl3 (an hnRNP involved in mRNA export via formation of export-competent ribonuclear protein complex [RNP]) to the active genes is facilitated by CBC. Thus, CBC enhances targeting of the export factors and promotes mRNA export. Such function of CBC is not mediated via THO and Sub2 of TREX, cleavage and polyadenylation factors, or Sus1 (that regulates mRNA export via transcription export 2 [TREX-2]). However, CBC promotes splicing ofSUS1mRNA and, consequently, Sus1 protein level and mRNA export via TREX-2. Collectively, our results support the hypothesis that CBC promotes recruitment of Yra1 and Npl3 to the active genes, independently of THO, Sub2, or cleavage and polyadenylation factors, and enhances mRNA export via TREX and RNP, respectively, in addition to its role in facilitatingSUS1mRNA splicing to increase mRNA export through TREX-2, revealing distinct stimulatory functions of CBC in mRNA export.

scholarly journals A Putative Arabidopsis Nucleoporin, AtNUP160, Is Critical for RNA Export and Required for Plant Tolerance to Cold Stress

2006 ◽  
Vol 26 (24) ◽  
pp. 9533-9543 ◽  
Author(s):  
Chun-Hai Dong ◽  
Xiangyang Hu ◽  
Weiping Tang ◽  
Xianwu Zheng ◽  
Yong Sig Kim ◽  
...  
Keyword(s):  
Cold Stress ◽  
Positional Cloning ◽  
Chilling Stress ◽  
Mrna Export ◽  
Nucleocytoplasmic Transport ◽  
Plant Responses ◽  
Plant Tolerance ◽  
Mrna In Situ Hybridization ◽  
Rna Export

ABSTRACT To study the genetic control of plant responses to cold stress, Arabidopsis thaliana mutants were isolated by a screen for mutations that impair cold-induced transcription of the CBF3-LUC reporter gene. We report here the characterization and cloning of a mutated gene, atnup160-1, which causes reduced CBF3-LUC induction under cold stress. atnup160-1 mutant plants display altered cold-responsive gene expression and are sensitive to chilling stress and defective in acquired freezing tolerance. AtNUP160 was isolated through positional cloning and shown to encode a putative homolog of the animal nucleoporin Nup160. In addition to the impaired expression of CBF genes, microarray analysis revealed that a number of other genes important for plant cold tolerance were also affected in the mutants. The atnup160 mutants flower early and show retarded seedling growth, especially at low temperatures. AtNUP160 protein is localized at the nuclear rim, and poly(A)-mRNA in situ hybridization shows that mRNA export is defective in the atnup160-1 mutant plants. Our study suggests that Arabidopsis AtNUP160 is critical for the nucleocytoplasmic transport of mRNAs and that it plays important roles in plant growth and flowering time regulation and is required for cold stress tolerance.

scholarly journals The Nuclear Pore Complex and mRNA Export in Cancer

Cancers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 42
Author(s):  
Katherine L. B. Borden
Keyword(s):  
Nuclear Pore Complex ◽  
Molecular Basis ◽  
Human Cancer ◽  
Mrna Export ◽  
Therapeutic Strategies ◽  
Chromosomal Translocations ◽  
Nuclear Pore ◽  
Specific Effects ◽  
Rna Export ◽  
Aberrant Rna

Export of mRNAs from the nucleus to the cytoplasm is a key regulatory step in the expression of proteins. mRNAs are transported through the nuclear pore complex (NPC). Export of mRNAs responds to a variety of cellular stimuli and stresses. Revelations of the specific effects elicited by NPC components and associated co-factors provides a molecular basis for the export of selected RNAs, independent of bulk mRNA export. Aberrant RNA export has been observed in primary human cancer specimens. These cargo RNAs encode factors involved in nearly all facets of malignancy. Indeed, the NPC components involved in RNA export as well as the RNA export machinery can be found to be dysregulated, mutated, or impacted by chromosomal translocations in cancer. The basic mechanisms associated with RNA export with relation to export machinery and relevant NPC components are described. Therapeutic strategies targeting this machinery in clinical trials is also discussed. These findings firmly position RNA export as a targetable feature of cancer along with transcription and translation.

scholarly journals A heterochromatin-specific RNA export pathway facilitates piRNA production

2019 ◽  
Author(s):  
Mostafa F. ElMaghraby ◽  
Peter Refsing Andersen ◽  
Florian Pühringer ◽  
Katharina Meixner ◽  
Thomas Lendl ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Mrna Export ◽  
Surveillance Systems ◽  
Rna Surveillance ◽  
Export Pathway ◽  
Transposon Silencing ◽  
Nuclear Rna ◽  
Rna Export ◽  
Non Coding Rnas ◽  
Pirna Pathway

PIWI-interacting RNAs (piRNAs) guide transposon silencing in animals. The 22-30nt piRNAs are processed in the cytoplasm from long non-coding RNAs. How piRNA precursors, which often lack RNA processing hallmarks of export-competent transcripts, achieve nuclear export is unknown. Here, we uncover the RNA export pathway specific for piRNA precursors in theDrosophilagermline. This pathway requires Nxf3-Nxt1, a variant of the hetero-dimeric mRNA export receptor Nxf1-Nxt1. Nxf3 interacts with UAP56, a nuclear RNA helicase essential for mRNA export, and CG13741/Bootlegger, which recruits Nxf3-Nxt1 and UAP56 to heterochromatic piRNA source loci. Upon RNA cargo binding, Nxf3 achieves nuclear export via the exportin Crm1, and accumulates together with Bootlegger in peri-nuclear nuage, suggesting that after export, Nxf3-Bootlegger delivers precursor transcripts to the piRNA processing sites. Our findings indicate that the piRNA pathway bypasses nuclear RNA surveillance systems to achieve export of heterochromatic, unprocessed transcripts to the cytoplasm, a strategy also exploited by retroviruses.

scholarly journals The Role of Nuclear Cap Binding Protein Cbc1p of Yeast in mRNA Termination and Degradation

2000 ◽  
Vol 20 (8) ◽  
pp. 2827-2838 ◽  
Author(s):  
Biswadip Das ◽  
Zijian Guo ◽  
Patrick Russo ◽  
Pascal Chartrand ◽  
Fred Sherman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mrna Export ◽  
Degradation Pathway ◽  
The Other ◽  
Nonsense Mutations ◽  
Mrna Surveillance ◽  
Nonessential Gene ◽  
Cap Binding Complex ◽  
Low Levels

ABSTRACT The cyc1-512 mutation in Saccharomyces cerevisiae causes a 90% reduction in the level of iso-1-cytochrome c because of the lack of a proper 3′-end-forming signal, resulting in low levels of eight aberrantly longcyc1-512 mRNAs which differ in length at their 3′ termini. cyc1-512 can be suppressed by deletion of either of the nonessential genes CBC1 and CBC2, which encode the CBP80 and CBP20 subunits of the nuclear cap binding complex, respectively, or by deletion of the nonessential gene UPF1, which encodes a major component of the mRNA surveillance complex. The upf1-Δ deletion suppressed the cyc1-512defect by diminishing degradation of the longer subset ofcyc1-512 mRNAs, suggesting that downstream elements or structures occurred in the extended 3′ region, similar to the downstream elements exposed by transcripts bearing premature nonsense mutations. On the other hand, suppression of cyc1-512defects by cbc1-Δ occurred by two different mechanisms. The levels of the shorter cyc1-512 transcripts were enhanced in the cbc1-Δ mutants by promoting 3′-end formation at otherwise-weak sites, whereas the levels of the longercyc1-512 transcripts, as well as of all mRNAs, were slightly enhanced by diminishing degradation. Furthermore,cbc1-Δ greatly suppressed the degradation of mRNAs and other phenotypes of a rat7-1 strain which is defective in mRNA export. We suggest that Cbc1p defines a novel degradation pathway that acts on mRNAs partially retained in nuclei.

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