scholarly journals Stress-induced inhibition of mRNA export triggers RNase III-mediated decay of the BDF2 mRNA

RNA ◽  
2021 ◽  
pp. rna.078880.121
Author(s):  
Charles Wang ◽  
Keaton W Barr ◽  
Dean Neutel ◽  
Kevin Roy ◽  
Yanru Liu ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Export ◽  
Mrna Export ◽  
Regulation Of Gene Expression ◽  
Stress Conditions ◽  
Rnase Iii ◽  
Nuclear Retention ◽  
Stem Loop ◽  
Multiple Stress ◽  
Global Inhibition

The expression of bromodomain-containing proteins that regulate chromatin structure and accessibility must be tightly controlled to ensure the appropriate regulation of gene expression. In the yeast S. cerevisiae, Bromodomain Factor 2 (BDF2) expression is extensively regulated post-transcriptionally during stress by RNase III-mediated decay (RMD), which is triggered by cleavage of the BDF2 mRNA in the nucleus by the RNase III homologue Rnt1p. Previous studies have shown that RMD-mediated down-regulation of BDF2 is hyper-activated in osmotic stress conditions, yet the mechanisms driving the enhanced nuclear cleavage of BDF2 RNA under these conditions remain unknown. Here, we show that RMD hyper-activation can be detected in multiple stress conditions that inhibit mRNA export, and that Rnt1p remains primarily localized in the nucleus during salt stress. We show that globally inhibiting mRNA nuclear export by anchoring away mRNA biogenesis or export factors out of the nucleus can recapitulate RMD hyper-activation in the absence of stress. RMD hyperactivation requires Rnt1p nuclear localization but does not depend on the BDF2 gene endogenous promoter, and its efficiency is affected by the structure of the stem-loop cleaved by Rnt1p. Because multiple stress conditions have been shown to mediate global inhibition of mRNA export, our results suggest that the hyperactivation of RMD is primarily the result of the increased nuclear retention of the BDF2 mRNA during stress.

scholarly journals Regulation of mRNA export through API5 and nuclear FGF2 interaction

2020 ◽  
Vol 48 (11) ◽  
pp. 6340-6352 ◽  
Author(s):  
Seoung Min Bong ◽  
Seung-Hyun Bae ◽  
Bomin Song ◽  
HyeRan Gwak ◽  
Seung-Won Yang ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Export ◽  
Mrna Export ◽  
Structural Basis ◽  
Nuclear Localization Sequence ◽  
Physical Interaction ◽  
Dynamic Regulation ◽  
Localization Sequence ◽  
Localization Signal ◽  
Apoptosis Inhibitor

Abstract API5 (APoptosis Inhibitor 5) and nuclear FGF2 (Fibroblast Growth Factor 2) are upregulated in various human cancers and are correlated with poor prognosis. Although their physical interaction has been identified, the function related to the resulting complex is unknown. Here, we determined the crystal structure of the API5–FGF2 complex and identified critical residues driving the protein interaction. These findings provided a structural basis for the nuclear localization of the FGF2 isoform lacking a canonical nuclear localization signal and identified a cryptic nuclear localization sequence in FGF2. The interaction between API5 and FGF2 was important for mRNA nuclear export through both the TREX and eIF4E/LRPPRC mRNA export complexes, thus regulating the export of bulk mRNA and specific mRNAs containing eIF4E sensitivity elements, such as c-MYC and cyclin D1. These data show the newly identified molecular function of API5 and nuclear FGF2, and provide a clue to understanding the dynamic regulation of mRNA export.

Effect of mutation of amino acids 246–251 (KRKHKK) in HSP72 on protein synthesis and recovery from hypoxic injury

2005 ◽  
Vol 289 (6) ◽  
pp. H2519-H2525 ◽  
Author(s):  
M. R. Voss ◽  
S. Gupta ◽  
J. P. Stice ◽  
G. Baumgarten ◽  
L. Lu ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Nuclear Localization ◽  
Nuclear Export ◽  
Cell Function ◽  
C2c12 Cells ◽  
Protective Effects ◽  
Nuclear Retention ◽  
Hypoxic Injury ◽  
Simulated Ischemia

Heat shock protein (HSP)72, the inducible form of HSP70, protects cells against a variety of injuries, but underlying mechanisms are poorly defined. To investigate the protective effects of HSP72, multiple clones expressing wild-type (WT) HSP72 and two mutants with defective nucleolar and nuclear localization (M45 and 985A, respectively) were made with the tet-off system in C2C12 cells. Four different parameters of cell function/injury were examined after simulated ischemia: protein synthesis, polysome formation, DNA synthesis, and lactate dehydrogenase (LDH release). Overexpression of WT HSP72 was also compared to nontransfected C2C12 cells. As expected, overexpression of HSP72 protected against simulated ischemia and reoxygenation for all parameters. In contrast, both M45 and 985A showed abnormal protein synthesis and polysome formation, both after simulated ischemia and under control conditions. Total RNA was slightly reduced in M45 and 985A at baseline, but 1 h after hypoxia, RNA levels were protected in all clones but significantly decreased in nontransfected C2C12 cells. Clones expressing 985A had nuclear retention of mRNA, suggesting that HSP72 is needed for nuclear export of RNA. All clones, both WT and mutant, had protection of DNA synthesis compared to C2C12 cells, but 985A had greater release of LDH after injury than any other group. These results support a multifactoral protective effect of HSP72, some aspects dependent on nuclear localization with stress and some not. The protection of protein synthesis and polysome formation, and abnormalities in these with the mutants, support a role for HSP72 in these processes both in the normal cell and in injury.

scholarly journals CaMKII and PKA-dependent phosphorylation co-regulate nuclear localization of HDAC4 in adult cardiomyocytes

2021 ◽  
Vol 116 (1) ◽  
Author(s):  
Kathryn G. Helmstadter ◽  
Senka Ljubojevic-Holzer ◽  
Brent M. Wood ◽  
Khanha D. Taheri ◽  
Simon Sedej ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Export ◽  
Ventricular Myocytes ◽  
Early Response ◽  
Confocal Imaging ◽  
Nuclear Accumulation ◽  
Nuclear Retention ◽  
Human Cardiomyocytes ◽  
Mediated Effects ◽  
In Cells

AbstractNuclear histone deacetylase 4 (HDAC4) represses MEF2-mediated transcription, implicated in the development of heart failure. CaMKII-dependent phosphorylation drives nucleus-to-cytoplasm HDAC4 shuttling, but protein kinase A (PKA) is also linked to HDAC4 translocation. However, the interplay of CaMKII and PKA in regulating adult cardiomyocyte HDAC4 translocation is unclear. Here we sought to determine the interplay of PKA- and CaMKII-dependent HDAC4 phosphorylation and translocation in adult mouse, rabbit and human ventricular myocytes. Confocal imaging and protein analyses revealed that inhibition of CaMKII—but not PKA, PKC or PKD—raised nucleo-to-cytoplasmic HDAC4 fluorescence ratio (FNuc/FCyto) by ~ 50%, indicating baseline CaMKII activity that limits HDAC4 nuclear localization. Further CaMKII activation (via increased extracellular [Ca2+], high pacing frequencies, angiotensin II or overexpression of CaM or CaMKIIδC) led to significant HDAC4 nuclear export. In contrast, PKA activation by isoproterenol or forskolin drove HDAC4 into the nucleus (raising FNuc/FCyto by > 60%). These PKA-mediated effects were abolished in cells pretreated with PKA inhibitors and in cells expressing mutant HDAC4 in S265/266A mutant. In physiological conditions where both kinases are active, PKA-dependent nuclear accumulation of HDAC4 was predominant in the very early response, while CaMKII-dependent HDAC4 export prevailed upon prolonged stimuli. This orchestrated co-regulation was shifted in failing cardiomyocytes, where CaMKII-dependent effects predominated over PKA-dependent response. Importantly, human cardiomyocytes showed similar CaMKII- and PKA-dependent HDAC4 shifts. Collectively, CaMKII limits nuclear localization of HDAC4, while PKA favors HDAC4 nuclear retention and S265/266 is essential for PKA-mediated regulation. These pathways thus compete in HDAC4 nuclear localization and transcriptional regulation in cardiac signaling.

scholarly journals The hnRNP C proteins contain a nuclear retention sequence that can override nuclear export signals.

1996 ◽  
Vol 134 (6) ◽  
pp. 1365-1373 ◽  
Author(s):  
S Nakielny ◽  
G Dreyfuss
Keyword(s):  
Nuclear Export ◽  
Mrna Export ◽  
Nucleocytoplasmic Transport ◽  
The Other ◽  
Nuclear Retention ◽  
Essential Step ◽  
Hnrnp Proteins ◽  
Interphase Cells ◽  
Hnrnp C ◽  
C Proteins

Nascent pre-mRNAs associate with the abundant heterogeneous nuclear RNP (hnRNP) proteins and remain associated with them throughout the time they are in the nucleus. The hnRNP proteins can be divided into two groups according to their nucleocytoplasmic transport properties. One group is completely restricted to the nucleus in interphase cells, whereas the other group, although primarily nuclear at steady state, shuttles between the nucleus and the cytoplasm. Nuclear export of the shuttling hnRNP proteins is mediated by nuclear export signals (NESs). Mounting evidence indicates that NES-bearing hnRNP proteins are mediators of mRNA export. The hnRNP C proteins are representative of the nonshuttling group of hnRNP proteins. Here we show that hnRNP C proteins are restricted to the nucleus not because they lack an NES, but because they bear a nuclear retention sequence (NRS) that is capable of overriding NESs. The NRS comprises approximately 78 amino acids and is largely within the auxiliary domain of hnRNP C1. We suggest that the removal of NRS-containing hnRNP proteins from pre-mRNA/mRNA is required for mRNA export from the nucleus and is an essential step in the pathway of gene expression.

scholarly journals Regulation of mRNA export by the PI3 kinase/AKT signal transduction pathway

2013 ◽  
Vol 24 (8) ◽  
pp. 1208-1221 ◽  
Author(s):  
Alexandre Jose Christino Quaresma ◽  
Rachel Sievert ◽  
Jeffrey A. Nickerson
Keyword(s):  
Signal Transduction ◽  
Nuclear Export ◽  
Mrna Export ◽  
Tight Binding ◽  
Signal Transduction Pathway ◽  
Pi3 Kinase ◽  
Akt Pathway ◽  
Exon Junction Complex ◽  
Nuclear Retention ◽  
Core Proteins

UAP56, ALY/REF, and NXF1 are mRNA export factors that sequentially bind at the 5′ end of a nuclear mRNA but are also reported to associate with the exon junction complex (EJC). To screen for signal transduction pathways regulating mRNA export complex assembly, we used fluorescence recovery after photobleaching to measure the binding of mRNA export and EJC core proteins in nuclear complexes. The fraction of UAP56, ALY/REF, and NXF1 tightly bound in complexes was reduced by drug inhibition of the phosphatidylinositide 3-kinase (PI3 kinase)/AKT pathway, as was the tightly bound fraction of the core EJC proteins eIF4A3, MAGOH, and Y14. Inhibition of the mTOR mTORC1 pathway decreased the tight binding of MAGOH. Inhibition of the PI3 kinase/AKT pathway increased the export of poly(A) RNA and of a subset of candidate mRNAs. A similar effect of PI3 kinase/AKT inhibition was observed for mRNAs from both intron-containing and intronless histone genes. However, the nuclear export of mRNAs coding for proteins targeted to the endoplasmic reticulum or to mitochondria was not affected by the PI3 kinase/AKT pathway. These results show that the active PI3 kinase/AKT pathway can regulate mRNA export and promote the nuclear retention of some mRNAs.

scholarly journals Nuclear localization of non-structural protein 1 and nucleocapsid protein of equine arteritis virus

2002 ◽  
Vol 83 (4) ◽  
pp. 795-800 ◽  
Author(s):  
Marieke A. Tijms ◽  
Yvonne van der Meer ◽  
Eric J. Snijder
Keyword(s):  
Nuclear Localization ◽  
Nuclear Export ◽  
Virus Assembly ◽  
Equine Arteritis Virus ◽  
Genome Replication ◽  
Structural Protein ◽  
Leptomycin B ◽  
Nuclear Retention ◽  
N Protein ◽  
Cytoplasmic Membranes

RNA synthesis (genome replication and subgenomic mRNA transcription) directed by equine arteritis virus (EAV; family Arteriviridae, order Nidovirales) occurs on modified cytoplasmic membranes to which most viral replicase subunits localize. Remarkably, a fraction of non-structural protein 1 (nsp1), a protein essential for transcription but dispensable for genome replication, is present in the host cell nucleus, in particular during the earlier stages of infection. Expression of GFP-tagged fusion proteins revealed that nsp1 is actively imported into the nucleus. Although the signals responsible for nsp1 transport could not be identified, our studies revealed that another EAV protein with a partially nuclear localization, the nucleocapsid (N) protein, utilizes the CRM1-mediated nuclear export pathway. Inactivation of this pathway with the drug leptomycin B resulted in the unexpected and immediate nuclear retention of all N protein molecules, thus revealing that the protein shuttles between cytoplasm and nucleus before playing its role in cytoplasmic virus assembly.

Heat shock and ethanol stress provoke distinctly different responses in 3′-processing and nuclear export of HSP mRNA in Saccharomyces cerevisiae

2008 ◽  
Vol 414 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Shingo Izawa ◽  
Takeomi Kita ◽  
Kayo Ikeda ◽  
Yoshiharu Inoue
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Transcriptional Activation ◽  
Nuclear Export ◽  
Mrna Export ◽  
Yeast Cells ◽  
Nuclear Accumulation ◽  
Ethanol Stress ◽  
Nuclear Retention ◽  
Eukaryotic Gene

Under conditions of heat shock at 42 °C, mRNAs of HSP (heat shock protein) genes are exported out of the nucleus, whereas bulk poly(A)+ (polyadenylated) mRNA shows a nuclear accumulation in Saccharomyces cerevisiae. Such a selective mRNA export seems an efficacious strategy of yeast cells to adapt rapidly to stress. Although ethanol stress (10%, v/v) as well as heat shock blocks the export of bulk poly(A)+ mRNA, the differences and/or similarity between heat shock and ethanol stress in the mechanisms of selective mRNA export still remain to be clarified. We found that ethanol stress induced transcriptional activation of a subset of yeast HSP genes; however, intriguingly, most such transcripts remained in the nucleus in a hyperadenylated state and, as a consequence, were not translated into HSPs. Elimination of ethanol resulted in a rapid shortening of the poly(A) tails of HSP mRNAs, loss of their nuclear retention, and the coincidental synthesis of the respective HSPs. Since HSP mRNAs are selectively exported from the nucleus in heat-shocked cells, yeast cells respond differently to ethanol stress and heat shock in the 3′-processing and transport of HSP mRNAs. Furthermore, these results also suggest that hyperadenylation and nuclear retention of mRNAs might be used as a means to control eukaryotic gene expression under stressed conditions.

scholarly journals Cellular stresses induce the nuclear accumulation of importin α and cause a conventional nuclear import block

2004 ◽  
Vol 165 (5) ◽  
pp. 617-623 ◽  
Author(s):  
Yoichi Miyamoto ◽  
Takuya Saiwaki ◽  
Junichi Yamashita ◽  
Yoshinari Yasuda ◽  
Ippei Kotera ◽  
...  
Keyword(s):  
Heat Shock ◽  
Nuclear Import ◽  
Nuclear Export ◽  
Stress Conditions ◽  
Nuclear Accumulation ◽  
Nuclear Retention ◽  
Heat Shock Cognate 70 ◽  
Importin Α ◽  
Response To Stress ◽  
Cellular Stresses

We report here that importin α accumulates reversibly in the nucleus in response to cellular stresses including UV irradiation, oxidative stress, and heat shock. The nuclear accumulation of importin α appears to be triggered by a collapse in the Ran gradient, resulting in the suppression of the nuclear export of importin α. In addition, nuclear retention and the importin β/Ran-independent import of importin α also facilitate its rapid nuclear accumulation. The findings herein show that the classical nuclear import pathway is down-regulated via the removal of importin α from the cytoplasm in response to stress. Moreover, whereas the nuclear accumulation of heat shock cognate 70 is more sensitive to heat shock than the other stresses, importin α is able to accumulate in the nucleus at all the stress conditions tested. These findings suggest that the stress-induced nuclear accumulation of importin α can be involved in a common physiological response to various stress conditions.

scholarly journals Nuclear RNA binding regulates TDP-43 nuclear localization and passive nuclear export

2021 ◽  
Author(s):  
Lauren Duan ◽  
Benjamin L. Zaepfel ◽  
Vasilisa Aksenova ◽  
Mary Dasso ◽  
Jeffrey D. Rothstein ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Export ◽  
Rna Binding ◽  
Nuclear Accumulation ◽  
Nuclear Pore ◽  
Nuclear Retention ◽  
Rna Recognition Motifs ◽  
Nuclear Abundance ◽  
Recognition Motifs

AbstractNuclear clearance of the DNA/RNA-binding protein TDP-43 is a pathologic hallmark of amyotrophic lateral sclerosis and frontotemporal dementia that remains unexplained. Moreover, our current understanding of TDP-43 nucleocytoplasmic shuttling does not fully explain the predominantly nuclear localization of TDP-43 in healthy cells. Here, we used permeabilized and live-cell models to investigate TDP-43 nuclear export and the role of RNA in TDP-43 localization. We show that TDP-43 nuclear efflux occurs in low-ATP conditions and independent of active mRNA export, consistent with export by passive diffusion through nuclear pore channels. TDP-43 nuclear residence requires binding to GU-rich nuclear intronic pre-mRNAs, based on the induction of TDP-43 nuclear efflux by RNase and GU-rich oligomers and TDP-43 nuclear retention conferred by pre-mRNA splicing inhibitors. Mutation of TDP-43 RNA recognition motifs disrupts TDP-43 nuclear accumulation and abolishes transcriptional blockade-induced TDP-43 nuclear efflux, demonstrating strict dependence of TDP-43 nuclear localization on RNA binding. Thus, the nuclear abundance of GU-rich intronic pre-mRNAs, as dictated by the balance of transcription and pre-mRNA processing, regulates TDP-43 nuclear sequestration and availability for passive nuclear export.

scholarly journals Identification and in Silico Characterization of Novel and Conserved MicroRNAs in Methyl Jasmonate-Stimulated Scots Pine (Pinus sylvestris L.) Needles

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 384
Author(s):  
Baiba Krivmane ◽  
Ilze Šņepste ◽  
Vilnis Šķipars ◽  
Igor Yakovlev ◽  
Carl Gunnar Fossdal ◽  
...  
Keyword(s):  
Methyl Jasmonate ◽  
Scots Pine ◽  
Target Genes ◽  
Regulation Of Gene Expression ◽  
Stem Loop ◽  
Protein Coding ◽  
Stem Loop Structure ◽  
In Silico Characterization ◽  
Potential Precursor

MicroRNAs (miRNAs) are non-protein coding RNAs of ~20–24 nucleotides in length that play an important role in many biological and metabolic processes, including the regulation of gene expression, plant growth and developmental processes, as well as responses to stress and pathogens. The aim of this study was to identify and characterize novel and conserved microRNAs expressed in methyl jasmonate-treated Scots pine needles. In addition, potential precursor sequences and target genes of the identified miRNAs were determined by alignment to the Pinus unigene set. Potential precursor sequences were identified using the miRAtool, conserved miRNA precursors were also tested for the ability to form the required stem-loop structure, and the minimal folding free energy indexes were calculated. By comparison with miRBase, 4975 annotated sequences were identified and assigned to 173 miRNA groups, belonging to a total of 60 conserved miRNA families. A total of 1029 potential novel miRNAs, grouped into 34 families were found, and 46 predicted precursor sequences were identified. A total of 136 potential target genes targeted by 28 families were identified. The majority of previously reported highly conserved plant miRNAs were identified in this study, as well as some conserved miRNAs previously reported to be monocot specific. No conserved dicot-specific miRNAs were identified. A number of potential gymnosperm or conifer specific miRNAs were found, shared among a range of conifer species.

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