scholarly journals A Yeast Homologue of Hsp70, Ssa1p, Regulates Turnover of the MFA2 Transcript through Its AU-Rich 3′ Untranslated Region

2003 ◽  
Vol 23 (8) ◽  
pp. 2623-2632 ◽  
Author(s):  
Radharani Duttagupta ◽  
Shobha Vasudevan ◽  
Carol J. Wilusz ◽  
Stuart W. Peltz
Keyword(s):  
Untranslated Region ◽  
Mrna Decay ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Rich Region ◽  
Rapid Decay ◽  
Chaperone Protein ◽  
Eukaryotic Mrnas ◽  
Necessary And Sufficient ◽  
Dependent Mechanism

ABSTRACT Many eukaryotic mRNAs exhibit regulated decay in response to cellular signals. AU-rich elements (AREs) identified in the 3′ untranslated region (3′-UTR) of several such mRNAs play a critical role in controlling the half-lives of these transcripts. The yeast ARE-containing mRNA, MFA2, has been studied extensively and is degraded by a deadenylation-dependent mechanism. However, the trans-acting factors that promote the rapid decay of MFA2 have not been identified. Our results suggest that the chaperone protein Hsp70, encoded by the SSA family of genes, is involved in modulating MFA2 mRNA decay. MFA2 is specifically stabilized in a strain bearing a temperature-sensitive mutation in the SSA1 gene. Furthermore, an AU-rich region within the 3′-UTR of the message is both necessary and sufficient to confer this regulation. Stabilization occurs as a result of slower deadenylation in the ssa1ts strain, suggesting that Hsp70 is required for activation of the turnover pathway.

scholarly journals Selective Degradation of AU-Rich mRNAs Promoted by the p37 AUF1 Protein Isoform

2003 ◽  
Vol 23 (18) ◽  
pp. 6685-6693 ◽  
Author(s):  
Bedabrata Sarkar ◽  
Qiaoran Xi ◽  
Cheng He ◽  
Robert J. Schneider
Keyword(s):  
Untranslated Region ◽  
Mrna Decay ◽  
Limiting Factors ◽  
Rapid Decay ◽  
Selective Degradation ◽  
Protein Isoform ◽  
Mrna Destabilization ◽  
Reporter Mrna ◽  
Cytokine Mrnas

ABSTRACT An AU-rich element (ARE) consisting of repeated canonical AUUUA motifs confers rapid degradation to many cytokine mRNAs when present in the 3′ untranslated region. Destabilization of mRNAs with AREs (ARE-mRNAs) is consistent with the interaction of ARE-binding proteins such as tristetraprolin and the four AUF1 isoforms. However, the association of the AUF1-mRNA interaction with decreased ARE-mRNA stability is correlative and has not been directly tested. We therefore determined whether overexpression of AUF1 isoforms promotes ARE-mRNA destabilization and whether AUF1 isoforms are limiting components for ARE-mRNA decay. We show that the p37 AUF1 isoform and, to a lesser extent, the p40 isoform possess ARE-mRNA-destabilizing activity when overexpressed. Surprisingly, overexpressed p37 AUF1 also destabilized reporter mRNAs containing a noncanonical but AU-rich 3′ untranslated region. Since overexpressed p37 AUF1 could interact in vivo with the AU-rich reporter mRNA, AUF1 may be involved in rapid turnover of mRNAs that lack canonical AREs. Moreover, overexpression of p37 AUF1 restored the ability of cells to rapidly degrade ARE-mRNAs when that ability was saturated and inhibited by overexpression of ARE-mRNAs. Finally, activation of ARE-mRNA decay often involves a translation-dependent step, which was eliminated by overexpression of p37 AUF1. These data indicate that the p37 AUF1 isoform and, to some extent, the p40 isoform are limiting factors that facilitate rapid decay of AU-rich mRNAs.

scholarly journals The 3′ Untranslated Region of Sindbis Virus Represses Deadenylation of Viral Transcripts in Mosquito and Mammalian Cells

2007 ◽  
Vol 82 (2) ◽  
pp. 880-892 ◽  
Author(s):  
Nicole L. Garneau ◽  
Kevin J. Sokoloski ◽  
Mateusz Opyrchal ◽  
C. Preston Neff ◽  
Carol J. Wilusz ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Untranslated Region ◽  
Sindbis Virus ◽  
Mrna Decay ◽  
Mosquito Cell ◽  
Productive Infection ◽  
Temperature Sensitive ◽  
Viral Mrnas ◽  
Cellular Mrnas

ABSTRACT The positive-sense transcripts of Sindbis virus (SINV) resemble cellular mRNAs in that they possess a 5′ cap and a 3′ poly(A) tail. It is likely, therefore, that SINV RNAs must successfully overcome the cytoplasmic mRNA decay machinery of the cell in order to establish an efficient, productive infection. In this study, we have taken advantage of a temperature-sensitive polymerase to shut off viral transcription, and we demonstrate that SINV RNAs are subject to decay during a viral infection in both C6/36 (Aedes albopictus) and baby hamster kidney cells. Interestingly, in contrast to most cellular mRNAs, the decay of SINV RNAs was not initiated by poly(A) tail shortening in either cell line except when most of the 3′ untranslated region (UTR) was deleted from the virus. This block in deadenylation of viral transcripts was recapitulated in vitro using C6/36 mosquito cell cytoplasmic extracts. Two distinct regions of the 319-base SINV 3′ UTR, the repeat sequence elements and a U-rich domain, were shown to be responsible for mediating the repression of deadenylation of viral mRNAs. Through competition studies performed in parallel with UV cross-linking and functional assays, mosquito cell factors—including a 38-kDa protein—were implicated in the repression of deadenylation mediated by the SINV 3′ UTR. This same 38-kDa protein was also implicated in mediating the repression of deadenylation by the 3′ UTR of another alphavirus, Venezuelan equine encephalitis virus. In summary, these data provide clear evidence that SINV transcripts do indeed interface with the cellular mRNA decay machinery during an infection and that the virus has evolved a way to avoid the major deadenylation-dependent pathway of mRNA decay.

scholarly journals Fluid flow-induced left-right asymmetric decay of Dand5 mRNA in the mouse embryo requires Bicc1-Ccr4 RNA degradation complex

2020 ◽  
Author(s):  
Katsura Minegishi ◽  
Benjamin Rothé ◽  
Kaoru R. Komatsu ◽  
Hiroki Ono ◽  
Yayoi Ikawa ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Mouse Embryo ◽  
Untranslated Region ◽  
Mrna Decay ◽  
Rna Binding ◽  
Flow Direction ◽  
Rna Degradation ◽  
Immotile Cilia ◽  
Necessary And Sufficient ◽  
Nucleotide Region

SUMMARYMolecular left-right (L-R) asymmetry is established at the node of the mouse embryo as a result of the sensing of a leftward fluid flow by immotile cilia of perinodal crown cells and the consequent degradation of Dand5 mRNA on the left side. We here examined how the fluid flow induces Dand5 mRNA decay. We found that the 3’ untranslated region (3’-UTR) of Dand5 mRNA is necessary and sufficient for the left-sided decay and is responsive to the flow direction, loss of the cation channel Pkd2, and Ca2+. The 200-nucleotide proximal-most portion of the 3’-UTR, which is conserved among mammals, is essential for the asymmetric mRNA decay and binds Bicc1, an RNA binding protein specifically expressed at the node. Bicc1 preferentially recognizes GAC and GACR sequences in RNA, and these motifs are enriched in the 200-nucleotide region of the Dand5 3’-UTR. The Cnot3 component of the Ccr4-Not deadenylase complex interacts with Bicc1 and is also required for Dand5 mRNA decay at the node. Our results thus suggest that leftward fluid flow induces binding of Bicc1 to the 3’-UTR of Dand5 mRNA in crown cells on the left side of the node, and that consequent recruitment of Ccr4-Not mediates mRNA degradation.

scholarly journals Fluid flow-induced left-right asymmetric decay of Dand5 mRNA in the mouse embryo requires a Bicc1-Ccr4 RNA degradation complex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Katsura Minegishi ◽  
Benjamin Rothé ◽  
Kaoru R. Komatsu ◽  
Hiroki Ono ◽  
Yayoi Ikawa ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Mouse Embryo ◽  
Untranslated Region ◽  
Mrna Decay ◽  
Rna Binding ◽  
Specific Binding ◽  
Flow Direction ◽  
Rna Degradation ◽  
Immotile Cilia ◽  
Necessary And Sufficient

AbstractMolecular left-right (L-R) asymmetry is established at the node of the mouse embryo as a result of the sensing of a leftward fluid flow by immotile cilia of perinodal crown cells and the consequent degradation of Dand5 mRNA on the left side. We here examined how the fluid flow induces Dand5 mRNA decay. We found that the first 200 nucleotides in the 3′ untranslated region (3′-UTR) of Dand5 mRNA are necessary and sufficient for the left-sided decay and to mediate the response of a 3′-UTR reporter transgene to Ca2+, the cation channel Pkd2, the RNA-binding protein Bicc1 and their regulation by the flow direction. We show that Bicc1 preferentially recognizes GACR and YGAC sequences, which can explain the specific binding to a conserved GACGUGAC motif located in the proximal Dand5 3′-UTR. The Cnot3 component of the Ccr4-Not deadenylase complex interacts with Bicc1 and is also required for Dand5 mRNA decay at the node. These results suggest that Ca2+ currents induced by leftward fluid flow stimulate Bicc1 and Ccr4-Not to mediate Dand5 mRNA degradation specifically on the left side of the node.

scholarly journals Regulated Intron Retention and Nuclear Pre-mRNA Decay Contribute toPABPN1Autoregulation

2015 ◽  
Vol 35 (14) ◽  
pp. 2503-2517 ◽  
Author(s):  
Danny Bergeron ◽  
Gheorghe Pal ◽  
Yves B. Beaulieu ◽  
Benoit Chabot ◽  
François Bachand
Keyword(s):  
Molecular Basis ◽  
Untranslated Region ◽  
Mrna Decay ◽  
Late Onset ◽  
Intron Retention ◽  
Oculopharyngeal Muscular Dystrophy ◽  
Rich Region ◽  
Functional Roles ◽  
Nuclear Exosome ◽  
Nuclear Transcript

The poly(A)-binding protein nuclear 1 is encoded by thePABPN1gene, whose mutations result in oculopharyngeal muscular dystrophy, a late-onset disorder for which the molecular basis remains unknown. Despite recent studies investigating the functional roles of PABPN1, little is known about its regulation. Here, we show that PABPN1 negatively controls its own expression to maintain homeostatic levels in human cells. Transcription from thePABPN1gene results in the accumulation of two major isoforms: an unspliced nuclear transcript that retains the 3′-terminal intron and a fully spliced cytoplasmic mRNA. Increased dosage of PABPN1 protein causes a significant decrease in the spliced/unspliced ratio, reducing the levels of endogenous PABPN1 protein. We also show that PABPN1 autoregulation requires inefficient splicing of its 3′-terminal intron. Our data suggest that autoregulation occurs via the binding of PABPN1 to an adenosine (A)-rich region in its 3′ untranslated region, which promotes retention of the 3′-terminal intron and clearance of intron-retained pre-mRNAs by the nuclear exosome. Our findings unveil a mechanism of regulated intron retention coupled to nuclear pre-mRNA decay that functions in the homeostatic control of PABPN1 expression.

scholarly journals Tracking the Cartoon mouse phenotype: Hemopexin domain–dependent regulation of MT1-MMP pericellular collagenolytic activity

2018 ◽  
Vol 293 (21) ◽  
pp. 8113-8127 ◽  
Author(s):  
Moustafa Sakr ◽  
Xiao-Yan Li ◽  
Farideh Sabeh ◽  
Tamar Y. Feinberg ◽  
John J. G. Tesmer ◽  
...  
Keyword(s):  
Cell Surface ◽  
Critical Role ◽  
Collagenolytic Activity ◽  
Temperature Sensitive ◽  
Type I ◽  
Permissive Temperature ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant ◽  
Golgi Network ◽  
Hemopexin Domain

Following ENU mutagenesis, a phenodeviant line was generated, termed the “Cartoon mouse,” that exhibits profound defects in growth and development. Cartoon mice harbor a single S466P point mutation in the MT1-MMP hemopexin domain, a 200-amino acid segment that is thought to play a critical role in regulating MT1-MMP collagenolytic activity. Herein, we demonstrate that the MT1-MMPS466P mutation replicates the phenotypic status of Mt1-mmp–null animals as well as the functional characteristics of MT1-MMP−/− cells. However, rather than a loss-of-function mutation acquired as a consequence of defects in MT1-MMP proteolytic activity, the S466P substitution generates a misfolded, temperature-sensitive mutant that is abnormally retained in the endoplasmic reticulum (ER). By contrast, the WT hemopexin domain does not play a required role in regulating MT1-MMP trafficking, as a hemopexin domain-deletion mutant is successfully mobilized to the cell surface and displays nearly normal collagenolytic activity. Alternatively, when MT1-MMPS466P–expressing cells are cultured at a permissive temperature of 25 °C that depresses misfolding, the mutant successfully traffics from the ER to the trans-Golgi network (ER → trans-Golgi network), where it undergoes processing to its mature form, mobilizes to the cell surface, and expresses type I collagenolytic activity. Together, these analyses define the Cartoon mouse as an unexpected gain-of-abnormal function mutation, wherein the temperature-sensitive mutant phenocopies MT1-MMP−/− mice as a consequence of eliciting a specific ER → trans-Golgi network trafficking defect.

Role of the chaperone protein 14-3-3ε in the regulation of influenza A virus-activated beta interferon

2021 ◽  
Author(s):  
Ee-Hong Tam ◽  
Yen-Chin Liu ◽  
Chian-Huey Woung ◽  
Helene Minyi Liu ◽  
Guan-Hong Wu ◽  
...  
Keyword(s):  
Virus Infection ◽  
Influenza A Virus ◽  
Influenza A ◽  
Critical Role ◽  
Type I ◽  
Type I Ifn ◽  
Ns1 Protein ◽  
Chaperone Protein ◽  
Influenza A Virus Infection

The NS1 protein of the influenza A virus plays a critical role in regulating several biological processes in cells, including the type I interferon (IFN) response. We previously profiled the cellular factors that interact with the NS1 protein of influenza A virus and found that the NS1 protein interacts with proteins involved in RNA splicing/processing, cell cycle regulation, and protein targeting processes, including 14-3-3ε. Since 14-3-3ε plays an important role in RIG-I translocation to MAVS to activate type I IFN expression, the interaction of the NS1 and 14-3-3ε proteins may prevent the RIG-I-mediated IFN response. In this study, we confirmed that the 14-3-3ε protein interacts with the N-terminal domain of the NS1 protein and that the NS1 protein inhibits RIG-I-mediated IFN-β promoter activation in 14-3-3ε-overexpressing cells. In addition, our results showed that knocking down 14-3-3ε can reduce IFN-β expression elicited by influenza A virus and enhance viral replication. Furthermore, we found that threonine in the 49 th amino acid position of the NS1 protein plays a role in the interaction with 14-3-3ε. Influenza A virus expressing C-terminus-truncated NS1 with T49A mutation dramatically increases IFN-β mRNA in infected cells and causes slower replication than that of virus without the T-to-A mutation. Collectively, this study demonstrates that 14-3-3ε is involved in influenza A virus-initiated IFN-β expression and that the interaction of the NS1 protein and 14-3-3ε may be one of the mechanisms for inhibiting type I IFN activation during influenza A virus infection. IMPORTANCE Influenza A virus is an important human pathogen causing severe respiratory disease. The virus has evolved several strategies to dysregulate the innate immune response and facilitate its replication. We demonstrate that the NS1 protein of influenza A virus interacts with the cellular chaperone protein 14-3-3ε, which plays a critical role in RIG-I translocation that induces type I IFN expression, and that NS1 protein prevents RIG-I translocation to mitochondrial membrane. The interaction site for 14-3-3ε is the RNA-binding domain (RBD) of the NS1 protein. Therefore, this research elucidates a novel mechanism by which the NS1 RBD mediates IFN-β suppression to facilitate influenza A viral replication. Additionally, the findings reveal the antiviral role of 14-3-3ε during influenza A virus infection.

scholarly journals A Critical Region in the FlaA Flagellin Facilitates Filament Formation of theVibrio choleraeFlagellum

2018 ◽  
Vol 200 (15) ◽  
Author(s):  
Mylea A. Echazarreta ◽  
Johnathan L. Kepple ◽  
Li-Hua Yen ◽  
Yue Chen ◽  
Karl E. Klose
Keyword(s):  
Diarrheal Disease ◽  
Critical Role ◽  
The Other ◽  
Class Iii ◽  
Content Type ◽  
Important Region ◽  
Filament Structure ◽  
Flagellar Filament ◽  
Necessary And Sufficient ◽  
Class Iv

ABSTRACTVibrio choleraeis a Gram-negative bacterium with a monotrichous flagellum that causes the human disease cholera. Flagellum-mediated motility is an integral part of the bacterial life cycle inside the host and in the aquatic environment. TheV. choleraeflagellar filament is composed of five flagellin subunits (FlaA, FlaB, FlaC, FlaD, and FlaE); however, only FlaA is necessary and sufficient for filament synthesis.flaAis transcribed from a class III flagellar promoter, whereas the other four flagellins are transcribed from class IV promoters. However, expressingflaAfrom a class IV promoter still facilitated motility in a strain that was otherwise lacking all five flagellins (ΔflaA-E). Furthermore, FlaA fromV. parahaemolyticus(FlaAVP; 77% identity) supported motility of theV. choleraeΔflaA-Estrain, whereas FlaA fromV. vulnificus(FlaAVV; 75% identity) did not, indicating that FlaA amino acid sequence is responsible for its critical role in flagellar synthesis. Chimeric proteins composed of different domains of FlaAVCand FlaD or FlaAVVrevealed that the N-terminal D1domain (D1N) contains an important region required for FlaA function. Further analyses of chimeric FlaAVC-FlaD proteins identified a lysine residue present at position 145 of the other flagellins but absent from FlaAVCthat can prevent monofilament formation. Moreover, the D1Nregion of amino acids 87 to 153 of FlaAVVinserted into FlaAVCallows monofilament formation but not motility, apparently due to the lack of filament curvature. These results identify residues within the D1Ndomain that allow FlaAVCto fold into a functional filament structure and suggest that FlaAVCassists correct folding of the other flagellins.IMPORTANCEV. choleraecauses the severe diarrheal disease cholera. Its ability to swim is mediated by rotation of a polar flagellum, and this motility is integral to its ability to cause disease and persist in the environment. The current studies illuminate how one specific flagellin (FlaA) within a multiflagellin structure mediates formation of the flagellar filament, thus allowingV. choleraeto swim. This knowledge can lead to safer vaccines and potential therapeutics to inhibit cholera.

Cold Chain Logistics in India

2016 ◽  
pp. 159-172 ◽  
Author(s):  
Swapnil Saurav ◽  
Ravi Potti
Keyword(s):  
Supply Chain ◽  
Fruits And Vegetables ◽  
Critical Role ◽  
High Energy ◽  
Cold Chain ◽  
Temperature Sensitive ◽  
Horticultural Crops ◽  
Perishable Goods ◽  
Power Deficit ◽  
Marine Products

Cold Chain refers to the transportation of temperature sensitive products like perishable goods from the point of origin to point of consumption in the food supply chain, which keeps it fresh and edible for a much longer period than in normal conditions. Cold Chain helps in transporting seasonal products and also making it available throughout the year. Two main parts of cold chain are transportation and storage systems. The key Indian industries where cold chain logistics play very important role are fruits and vegetables, milk and milk products (ice cream), Poultry and processed meat, marine products, pharmaceutical (mainly vaccines) and chemicals. An efficient cold chain industry ensures availability of food products as well as prevents spoilage of medicines. Country like India, where infrastructure is one of the major challenges, cold chain plays a critical role. Analysis for this study shows that cold supply chain network does not differ significantly from products to products at least in Indian scenario. Some of the challenges to the growth of sector in India are high energy cost, power deficit, rising real estate cost, lack of logistical support and uneven distribution of capacity. All these challenges bring down the operating margin of a company and makes it not so attractive business sector. But during last couple of years there is a positive environment being created for this sector in India. The growth in organized retail, growing interest in horticultural crops, demand for cold chain logistics from Pharmaceutical industry and various initiatives by government are some of the reasons why there is a renewed interest in this sector especially by private sector players. This study, which is focused on Indian cold chain logistics, analyzes the industry on PEST (Political, Economy, Social and Technology) model and presents top 3 factors on each of these 4 parameters.

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