scholarly journals The Dbp5 cycle at the nuclear pore complex during mRNA export I: dbp5 mutants with defects in RNA binding and ATP hydrolysis define key steps for Nup159 and Gle1

2011 ◽  
Vol 25 (10) ◽  
pp. 1052-1064 ◽  
Author(s):  
C. A. Hodge ◽  
E. J. Tran ◽  
K. N. Noble ◽  
A. R. Alcazar-Roman ◽  
R. Ben-Yishay ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Rna Binding ◽  
Atp Hydrolysis ◽  
Mrna Export ◽  
Nuclear Pore ◽  
Key Steps

scholarly journals Imaging within single NPCs reveals NXF1’s role in mRNA export on the cytoplasmic side of the pore

2019 ◽  
Vol 218 (9) ◽  
pp. 2962-2981 ◽  
Author(s):  
Rakefet Ben-Yishay ◽  
Amir Mor ◽  
Amit Shraga ◽  
Asaf Ashkenazy-Titelman ◽  
Noa Kinor ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Protein Interactions ◽  
Rna Binding ◽  
Mrna Export ◽  
Living Cells ◽  
Nuclear Pore ◽  
Protein Protein Interactions ◽  
Superresolution Microscopy ◽  
Directional Flow ◽  
Cytoplasmic Side

Translocation of mRNA through the nuclear pore complex (NPC) requires interactions with different NPC regions. To determine the interactions that are crucial for effective mRNA export in living cells, we examined mRNA export within individual pores by applying various types of mRNA export blocks that stalled mRNPs at different stages of transition. Focusing on the major mRNA export factor NXF1, we found that initial mRNP binding to the NPC did not require NXF1 in the NPC, whereas release into the cytoplasm did. NXF1 localization in the NPC did not require RNA or RNA binding. Superresolution microscopy showed that NXF1 consistently occupied positions on the cytoplasmic side of the NPC. Interactions with specific nucleoporins were pinpointed using FLIM-FRET for measuring protein–protein interactions inside single NPCs, showing that Dbp5 helicase activity of mRNA release is conserved in yeast and humans. Altogether, we find that specific interactions on the cytoplasmic side of the NPC are fundamental for the directional flow of mRNA export.

scholarly journals Mex67p of Schizosaccharomyces pombeInteracts with Rae1p in Mediating mRNA Export

2000 ◽  
Vol 20 (23) ◽  
pp. 8767-8782 ◽  
Author(s):  
Jin Ho Yoon ◽  
Dona C. Love ◽  
Anjan Guhathakurta ◽  
John A. Hanover ◽  
Ravi Dhar
Keyword(s):  
Nuclear Export ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Synthetic Lethality ◽  
Sequence Similarity ◽  
Mrna Export ◽  
Nuclear Periphery ◽  
Nuclear Pore ◽  
Multicopy Suppressor ◽  
Accessory Factor

ABSTRACT We identified the Schizosaccharomyces pombe mex67 gene (spmex67) as a multicopy suppressor of rae1-167 nup184-1 synthetic lethality and the rae1-167 tsmutation. spMex67p, a 596-amino-acid-long protein, has considerable sequence similarity to the Saccharomyces cerevisiae Mex67p (scMex67p) and human Tap. In contrast toscMEX67, spmex67 is essential for neither growth nor nuclear export of mRNA. However, an spmex67 null mutation (Δmex67) is synthetically lethal with therae1-167 mutation and accumulates poly(A)+ RNA in the nucleus. We identified a central region (149 to 505 amino acids) within spMex67p that associates with a complex containing Rae1p that complements growth and mRNA export defects of therae1-167 Δmex67 synthetic lethality. This region is devoid of RNA-binding, N-terminal nuclear localization, and the C-terminal nuclear pore complex-targeting regions. The (149–505)-green fluorescent protein (GFP) fusion is found diffused throughout the cell. Overexpression of spMex67p inhibits growth and mRNA export and results in the redistribution of the diffused localization of the (149–505)-GFP fusion to the nucleus and the nuclear periphery. These results suggest that spMex67p competes for essential mRNA export factor(s). Finally, we propose that the 149–505 region of spMex67p could act as an accessory factor in Rae1p-dependent transport and that spMex67p participates at various common steps with Rae1p export complexes in promoting the export of mRNA.

scholarly journals Linking key steps of microRNA biogenesis by TREX-2 and the nuclear pore complex in Arabidopsis

Nature Plants ◽  
2020 ◽  
Vol 6 (8) ◽  
pp. 957-969 ◽  
Author(s):  
Bailong Zhang ◽  
Chenjiang You ◽  
Yong Zhang ◽  
Liping Zeng ◽  
Jun Hu ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Pore ◽  
Microrna Biogenesis ◽  
Key Steps

scholarly journals An agent-based model for mRNA export through the nuclear pore complex

2014 ◽  
Vol 25 (22) ◽  
pp. 3643-3653 ◽  
Author(s):  
Mohammad Azimi ◽  
Evgeny Bulat ◽  
Karsten Weis ◽  
Mohammad R. K. Mofrad
Keyword(s):  
Nuclear Pore Complex ◽  
Mrna Export ◽  
Nuclear Pore ◽  
Central Channel ◽  
Agent Based Model ◽  
Agent Based ◽  
Transport Dynamics ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

mRNA export from the nucleus is an essential step in the expression of every protein- coding gene in eukaryotes, but many aspects of this process remain poorly understood. The density of export receptors that must bind an mRNA to ensure export, as well as how receptor distribution affects transport dynamics, is not known. It is also unclear whether the rate-limiting step for transport occurs at the nuclear basket, in the central channel, or on the cytoplasmic face of the nuclear pore complex. Using previously published biophysical and biochemical parameters of mRNA export, we implemented a three-dimensional, coarse-grained, agent-based model of mRNA export in the nanosecond regime to gain insight into these issues. On running the model, we observed that mRNA export is sensitive to the number and distribution of transport receptors coating the mRNA and that there is a rate-limiting step in the nuclear basket that is potentially associated with the mRNA reconfiguring itself to thread into the central channel. Of note, our results also suggest that using a single location-monitoring mRNA label may be insufficient to correctly capture the time regime of mRNA threading through the pore and subsequent transport. This has implications for future experimental design to study mRNA transport dynamics.

scholarly journals The Great Escape: mRNA Export through the Nuclear Pore Complex

2021 ◽  
Vol 22 (21) ◽  
pp. 11767
Author(s):  
Paola De Magistris
Keyword(s):  
Conformational Changes ◽  
Nuclear Pore Complex ◽  
Nuclear Export ◽  
Messenger Rna ◽  
Mrna Export ◽  
Protein Translation ◽  
Nuclear Pore ◽  
Body Of Knowledge ◽  
Transport Receptors ◽  
Basic Characteristics

Nuclear export of messenger RNA (mRNA) through the nuclear pore complex (NPC) is an indispensable step to ensure protein translation in the cytoplasm of eukaryotic cells. mRNA is not translocated on its own, but it forms ribonuclear particles (mRNPs) in association with proteins that are crucial for its metabolism, some of which; like Mex67/MTR2-NXF1/NXT1; are key players for its translocation to the cytoplasm. In this review, I will summarize our current body of knowledge on the basic characteristics of mRNA export through the NPC. To be granted passage, the mRNP cargo needs to bind transport receptors, which facilitate the nuclear export. During NPC transport, mRNPs undergo compositional and conformational changes. The interactions between mRNP and the central channel of NPC are described; together with the multiple quality control steps that mRNPs undergo at the different rings of the NPC to ensure only proper export of mature transcripts to the cytoplasm. I conclude by mentioning new opportunities that arise from bottom up approaches for a mechanistic understanding of nuclear export.

scholarly journals Specialization of chromatin-bound nuclear pore complexes promotes yeast aging

2021 ◽  
Author(s):  
Anne C Meinema ◽  
Theo Aspert ◽  
Sung Sik Lee ◽  
Gilles Charvin ◽  
Yves Barral
Keyword(s):  
Quality Control ◽  
Nuclear Pore Complex ◽  
Mrna Export ◽  
Yeast Cells ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Replicative Lifespan ◽  
Yeast Aging ◽  
Key Drivers ◽  
Pore Complexes

The nuclear pore complex (NPC) mediates nearly all exchanges between nucleus and cytoplasm, and changes composition in many species as the organism ages. However, how these changes arise and whether they contribute themselves to aging is poorly understood. We show that in replicatively aging yeast cells attachment of DNA circles to NPCs drives the displacement of the NPCs’ nuclear basket and cytoplasmic complexes. Remodeling of the NPC resulted from the regulation of basket components by SAGA, rather than from damages. These changes affected NPC interaction with mRNA export factors, without affecting the residence of import factors or engaging the NPC quality control machinery. Mutations preventing NPC remodeling extended the replicative lifespan of the cells. Thus, our data indicate that DNA circles accumulating in the mother cell drive aging at least in part by triggering NPC specialization. We suggest that antagonistic pleiotropic effects of NPC specialization are key drivers of aging.

SARS coronavirus protein nsp1 disrupts localization of Nup93 from the nuclear pore complex

2019 ◽  
Vol 97 (6) ◽  
pp. 758-766 ◽  
Author(s):  
Garret N. Gomez ◽  
Fareeha Abrar ◽  
Maya P. Dodhia ◽  
Fabiola G. Gonzalez ◽  
Anita Nag
Keyword(s):  
Gene Expression ◽  
Nuclear Pore Complex ◽  
Rna Binding ◽  
Nonstructural Protein ◽  
Nuclear Lamina ◽  
Host Gene ◽  
Nuclear Pore ◽  
Host Gene Expression ◽  
Nonstructural Protein 1 ◽  
Cytoplasmic Transport

Severe acute respiratory syndrome coronavirus nonstructural protein 1 (nsp1) is a key factor in virus-induced down-regulation of host gene expression. In infected cells, nsp1 engages in a multipronged mechanism to inhibit host gene expression by binding to the 40S ribosome to block the assembly of translationally competent ribosome, and then inducing endonucleolytic cleavage and the degradation of host mRNAs. Here, we report a previously undetected mechanism by which nsp1 exploits the nuclear pore complex and disrupts the nuclear–cytoplasmic transport of biomolecules. We identified members of the nuclear pore complex from the nsp1-associated protein assembly and found that the expression of nsp1 in HEK cells disrupts Nup93 localization around the nuclear envelope without triggering proteolytic degradation, while the nuclear lamina remains unperturbed. Consistent with its role in host shutoff, nsp1 alters the nuclear–cytoplasmic distribution of an RNA binding protein, nucleolin. Our results suggest that nsp1, alone, can regulate multiple steps of gene expression including nuclear–cytoplasmic transport.

The RNA-binding protein DRBD18 regulates processing and export of the mRNA encoding Trypanosoma brucei RNA-binding protein 10

2021 ◽  
Author(s):  
Tania Bishola Tshitenge ◽  
Bin Liu ◽  
Christine Clayton
Keyword(s):  
Trypanosoma Brucei ◽  
Rna Binding ◽  
Gene Expression Regulation ◽  
Binding Protein ◽  
Mrna Export ◽  
Rna Binding Protein ◽  
Tsetse Flies ◽  
Nuclear Pore ◽  
Regulatory Sequences ◽  
Mrna Isoforms

The parasite Trypanosoma brucei grows as bloodstream forms in mammalian hosts, and as procyclic forms in tsetse flies. Trypanosome protein coding genes are arranged in polycistronic transcription units, so gene expression regulation depends heavily on post-transcriptional mechanisms. The essential RNA-binding protein RBP10 is expressed only in mammalian-infective forms, where it targets procyclic-specific mRNAs for destruction. We show that developmental regulation of RBP10 expression is mediated by the exceptionally long 7.3 Kb 3'-UTR of its mRNA. Different regulatory sequences that can independently enhance mRNA stability and translation in bloodstream forms, or destabilize and repress translation in procyclic forms, are scattered throughout the 3'-UTR. The RNA-binding protein DRBD18 is implicated in the export of a subset of mRNAs from the nucleus in procyclic forms. We confirmed that in bloodstream forms, DRBD18 copurifies the outer ring of the nuclear pore, mRNA export proteins and exon junction complex proteins. Loss of DRBD18 in bloodstream forms caused accumulation of several shortened RBP10 mRNA isoforms, with loss of longer species, but RNAi targeting the essential export factor MEX67 did not cause such changes, demonstrating specificity. Long RBP10 mRNAs accumulated in the nucleus, while shorter ones reached the cytoplasm. We suggest that DRBD18 binds to processing signals in the RBP10 3'-UTR, simultaneously preventing their use and recruiting mRNA export factors. DRBD18 depletion caused truncation of the 3'-UTRs of more than 100 other mRNAs, suggesting that it has an important role in regulating use of alternative processing sites.

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.

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