scholarly journals Decoying the cap- mRNA degradation system by a double-stranded RNA virus and poly(A)- mRNA surveillance by a yeast antiviral system.

1995 ◽  
Vol 15 (5) ◽  
pp. 2763-2771 ◽  
Author(s):  
D C Masison ◽  
A Blanc ◽  
J C Ribas ◽  
K Carroll ◽  
N Sonenberg ◽  
...  
Keyword(s):  
Rna Virus ◽  
Mrna Level ◽  
Killer Toxin ◽  
Toxin Production ◽  
Double Stranded Rna ◽  
Copy Numbers ◽  
Cellular Mrnas ◽  
Rna Replicon

The major coat protein of the L-A double-stranded RNA virus of Saccharomyces cerevisiae covalently binds m7 GMP from 5' capped mRNAs in vitro. We show that this cap binding also occurs in vivo and that, while this activity is required for expression of viral information (killer toxin mRNA level and toxin production) in a wild-type strain, this requirement is suppressed by deletion of SKI1/XRN1/SEP1. We propose that the virus creates decapped cellular mRNAs to decoy the 5'-->3' exoribonuclease specific for cap- RNA encoded by XRN1. The SKI2 antiviral gene represses the copy numbers of the L-A and L-BC viruses and the 20S RNA replicon, apparently by specifically blocking translation of viral RNA. We show that SKI2, SKI3, and SKI8 inhibit translation of electroporated luciferase and beta-glucuronidase mRNAs in vivo, but only if they lack the 3' poly(A) structure. Thus, L-A decoys the SKI1/XRN1/SEP1 exonuclease directed at 5' uncapped ends, but translation of the L-A poly(A)- mRNA is repressed by Ski2,3,8p. The SKI2-SKI3-SKI8 system is more effective against cap+ poly(A)- mRNA, suggesting a (nonessential) role in blocking translation of fragmented cellular mRNAs.

scholarly journals His-154 is involved in the linkage of the Saccharomyces cerevisiae L-A double-stranded RNA virus Gag protein to the cap structure of mRNAs and is essential for M1 satellite virus expression.

1994 ◽  
Vol 14 (4) ◽  
pp. 2664-2674 ◽  
Author(s):  
A Blanc ◽  
J C Ribas ◽  
R B Wickner ◽  
N Sonenberg
Keyword(s):  
Rna Virus ◽  
Specific Binding ◽  
Covalent Bond ◽  
Gag Protein ◽  
Double Stranded Rna ◽  
Satellite Virus ◽  
Eukaryotic Mrnas ◽  
Virus Expression

The coat protein (Gag) of the double-stranded RNA virus L-A was previously shown to form a covalent bond with the cap structure of eukaryotic mRNAs. Here, we identify the linkage as a phosphoroimidazole bond between the alpha phosphate of the cap structure and a nitrogen in the Gag protein His-154 imidazole side chain. Mutations of His-154 abrogate the ability of Gag to bind to the cap structure, without affecting cap recognition, in vivo virus particle formation from an L-A cDNA clone, or in vitro specific binding and replication of plus-stranded single-stranded RNA. However, genetic analyses demonstrate that His-154 is essential for M1 satellite virus expression.

His-154 is involved in the linkage of the Saccharomyces cerevisiae L-A double-stranded RNA virus Gag protein to the cap structure of mRNAs and is essential for M1 satellite virus expression

1994 ◽  
Vol 14 (4) ◽  
pp. 2664-2674
Author(s):  
A Blanc ◽  
J C Ribas ◽  
R B Wickner ◽  
N Sonenberg
Keyword(s):  
Rna Virus ◽  
Specific Binding ◽  
Covalent Bond ◽  
Gag Protein ◽  
Double Stranded Rna ◽  
Satellite Virus ◽  
Eukaryotic Mrnas ◽  
Virus Expression

The coat protein (Gag) of the double-stranded RNA virus L-A was previously shown to form a covalent bond with the cap structure of eukaryotic mRNAs. Here, we identify the linkage as a phosphoroimidazole bond between the alpha phosphate of the cap structure and a nitrogen in the Gag protein His-154 imidazole side chain. Mutations of His-154 abrogate the ability of Gag to bind to the cap structure, without affecting cap recognition, in vivo virus particle formation from an L-A cDNA clone, or in vitro specific binding and replication of plus-stranded single-stranded RNA. However, genetic analyses demonstrate that His-154 is essential for M1 satellite virus expression.

scholarly journals Topical Application of Double-Stranded RNA Targeting 2b and CP Genes of Cucumber mosaic virus Protects Plants against Local and Systemic Viral Infection

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 963
Author(s):  
Maria C. Holeva ◽  
Athanasios Sklavounos ◽  
Rajendran Rajeswaran ◽  
Mikhail M. Pooggin ◽  
Andreas E. Voloudakis
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Topical Application ◽  
Plant Virus ◽  
Plant Protection ◽  
Post Inoculation ◽  
Tobacco Plants ◽  
Double Stranded Rna

Cucumber mosaic virus (CMV) is a destructive plant virus with worldwide distribution and the broadest host range of any known plant virus, as well as a model plant virus for understanding plant–virus interactions. Since the discovery of RNA interference (RNAi) as a major antiviral defense, RNAi-based technologies have been developed for plant protection against viral diseases. In plants and animals, a key trigger of RNAi is double-stranded RNA (dsRNA) processed by Dicer and Dicer-like (DCL) family proteins in small interfering RNAs (siRNAs). In the present study, dsRNAs for coat protein (CP) and 2b genes of CMV were produced in vitro and in vivo and applied onto tobacco plants representing a systemic solanaceous host as well as on a local host plant Chenopodium quinoa. Both dsRNA treatments protected plants from local and systemic infection with CMV, but not against infection with unrelated viruses, confirming sequence specificity of antiviral RNAi. Antiviral RNAi was effective when dsRNAs were applied simultaneously with or four days prior to CMV inoculation, but not four days post inoculation. In vivo-produced dsRNAs were more effective than the in vitro-produced; in treatments with in vivo dsRNAs, dsRNA-CP was more effective than dsRNA-2b, while the effects were opposite with in vitro dsRNAs. Illumina sequencing of small RNAs from in vivo dsRNA-CP treated and non-treated tobacco plants revealed that interference with CMV infection in systemic leaves coincides with strongly reduced accumulation of virus-derived 21- and 22-nucleotide (nt) siRNAs, likely generated by tobacco DCL4 and DCL2, respectively. While the 21-nt class of viral siRNAs was predominant in non-treated plants, 21-nt and 22-nt classes accumulated at almost equal (but low) levels in dsRNA treated plants, suggesting that dsRNA treatment may boost DCL2 activity. Taken together, our findings confirm the efficacy of topical application of dsRNA for plant protection against viruses and shed more light on the mechanism of antiviral RNAi.

scholarly journals The Potential Role of IL1RAP on Tumor Microenvironment-Related Inflammatory Factors in Stomach Adenocarcinoma

2021 ◽  
Vol 20 ◽  
pp. 153303382199528
Author(s):  
Qing Lv ◽  
Qinghua Xia ◽  
Anshu Li ◽  
Zhiyong Wang
Keyword(s):  
Tumor Microenvironment ◽  
Interleukin 1 ◽  
Mrna Level ◽  
Inflammatory Factors ◽  
Stomach Carcinoma ◽  
Downstream Target ◽  
Volume Weight

This study was performed to investigate the role of interleukin-1 receptor accessory protein (IL1RAP) in stomach carcinoma in vitro and in vivo, determine whether IL1RAP knockdown could regulate the development of stomach carcinoma, and elucidate the relationship between IL1RAP knockdown and inflammation by tumor microenvironment-related inflammatory factors in stomach carcinoma. We first used TCGA and GEPIA systems to predict the potential function of IL1RAP. Second, western blot and RT-PCR were used to analyze the expression, or mRNA level, of IL1RAP at different tissue or cell lines. Third, the occurrence and development of stomach carcinoma in vitro and in vivo were observed by using IL1RAP knockdown lentivirus. Finally, the inflammation of stomach carcinoma in vitro and in vivo was observed. Results show that in GEPIA and TCGA systems, IL1RAP expression in STAD tumor tissue was higher than normal, and high expression of IL1RAP in STAD patients had a worse prognostic outcome. Besides, GSEA shown IL1RAP was negative correlation of apopopsis, TLR4 and NF-κB signaling pathway. We also predicted that IL1RAP may related to IL-1 s, IL-33, and IL-36 s in STAD. The IL1RAP expression and mRNA level in tumor, or MGC803, cells were increased. Furthermore, IL1RAP knockdown by lentivirus could inhibit stomach carcinoma development in vitro and in vivo through weakening tumor cell proliferation, migration, invasion, therefore reducing tumor volume, weight, and biomarker levels, and increasing apoptotic level. Finally, we found IL1RAP knockdown could increase inflammation of tumor microenvironment-related inflammatory factors of stomach carcinoma, in vitro and in vivo. Our study demonstrates that IL1RAP is possibly able to regulate inflammation and apoptosis in stomach carcinoma. Furthermore, TLR4, NF-κB, IL-1 s, IL-33, and IL-36 s maybe the downstream target factor of IL1RAP in inflammation. These results may provide a new strategy for stomach carcinoma development by regulating inflammation.

scholarly journals Regulatory Mechanism for Exfoliative Toxin Production inStaphylococcus aureus

2011 ◽  
Vol 79 (4) ◽  
pp. 1660-1670 ◽  
Author(s):  
Fuminori Kato ◽  
Noriko Kadomoto ◽  
Yuko Iwamoto ◽  
Katsuaki Bunai ◽  
Hitoshi Komatsuzawa ◽  
...  
Keyword(s):  
Mouse Model ◽  
Regulatory Mechanism ◽  
Toxin Production ◽  
Neonatal Mouse ◽  
Epidermal Keratinocytes ◽  
Global Regulators ◽  
Exfoliative Toxin ◽  
Blistering Disease

ABSTRACTThe exfoliative toxin (ET) is a major virulence factor ofStaphylococcus aureusthat causes bullous impetigo and its disseminated form, staphylococcal scalded-skin syndrome (SSSS). ET selectively digests one of the intracellular adhesion molecules, desmoglein 1, of epidermal keratinocytes and causes blisters due to intraepidermal cell-cell dissociation. MostS. aureusstrains that cause blistering disease produce either ETA or ETB. They are serologically distinct molecules, where ETA is encoded on a phage genome and ETB is enocded on a large plasmid. ETA-producingS. aureusstrains are frequently isolated from impetigo patients, and ETB-producingS. aureusstrains are isolated from SSSS. ET-induced blister formation can be reproduced with the neonatal mouse. To determine the regulatory mechanism of ET production, we investigated the role of the two-component systems and global regulators foretaoretbexpressionin vitroandin vivowith the mouse model. Western blot and transcription analyses using a series of mutants demonstrate ETA production was downregulated bysigB,sarS, andsarA, while ETB production was downregulated bysigBandsarAbut not bysarS. Production of both toxins is upregulated bysaeRS,arlRS, andagrCA. Furthermore, by thein vivoneonatal mouse model,sigBandsarSbut notsarAnegatively regulate the exfoliation activity of the ETA-producing strain, whilesarAnegatively regulates the ETB-producing strain. In both strains,saeRS,arlRS, andagrCApositively regulate the exfoliation activityin vivo. The data illustrate similar but distinct regulatory mechanisms for ETA and ETB productionin S. aureus in vitroas well asin vivo.

scholarly journals Toxin Production by Pseudomonas Tolaasii Paine

1973 ◽  
Vol 26 (2) ◽  
pp. 509 ◽  
Author(s):  
NG Nair ◽  
PC Fahy
Keyword(s):  
Toxin Production ◽  
Nutrient Broth ◽  
Dialysis Membrane ◽  
Pseudomonas Tolaasii ◽  
Brown Discoloration

Evidence is presented for the production of toxin in vitro and in vivo by P. tolaasii. Nutrient broth suspensions of P. tolaasii placed on detached mushroom sporophores but separated by a dialysis membrane caused brown discoloration and slightly sunken lesions.

scholarly journals Repression and Derepression of Minus-Strand Synthesis in a Plus-Strand RNA Virus Replicon

2004 ◽  
Vol 78 (14) ◽  
pp. 7619-7633 ◽  
Author(s):  
Guohua Zhang ◽  
Jiuchun Zhang ◽  
Anne E. Simon
Keyword(s):  
Solution Structure ◽  
Rna Virus ◽  
Structural Features ◽  
General Mechanism ◽  
Minus Strand ◽  
Turnip Crinkle Virus ◽  
Structural Elements ◽  
Transcription In Vitro

ABSTRACT Plus-strand viral RNAs contain sequences and structural elements that allow cognate RNA-dependent RNA polymerases (RdRp) to correctly initiate and transcribe asymmetric levels of plus and minus strands during RNA replication. cis-acting sequences involved in minus-strand synthesis, including promoters, enhancers, and, recently, transcriptional repressors (J. Pogany, M. R. Fabian, K. A. White, and P. D. Nagy, EMBO J. 22:5602-5611, 2003), have been identified for many viruses. A second example of a transcriptional repressor has been discovered in satC, a replicon associated with turnip crinkle virus. satC hairpin 5 (H5), located proximal to the core hairpin promoter, contains a large symmetrical internal loop (LSL) with sequence complementary to 3′-terminal bases. Deletion of satC 3′-terminal bases or alteration of the putative interacting bases enhanced transcription in vitro, while compensatory exchanges between the LSL and 3′ end restored near-normal transcription. Solution structure analysis indicated that substantial alteration of the satC H5 region occurs when the three 3′-terminal cytidylates are deleted. These results indicate that H5 functions to suppress synthesis of minus strands by sequestering the 3′ terminus from the RdRp. Alteration of a second sequence strongly repressed transcription in vitro and accumulation in vivo, suggesting that this sequence may function as a derepressor to free the 3′ end from interaction with H5. Hairpins with similar sequence and/or structural features that contain sequence complementary to 3′-terminal bases, as well as sequences that could function as derepressors, are located in similar regions in other carmoviruses, suggesting a general mechanism for controlling minus-strand synthesis in the genus.

scholarly journals Autophagy and Ubiquitin-Mediated Proteolytic Degradation of PML/Rarα Fusion Protein in Matrine-Induced Differentiation Sensitivity Recovery of ATRA-Resistant APL (NB4-LR1) Cells: in Vitro and in Vivo Studies

2018 ◽  
Vol 48 (6) ◽  
pp. 2286-2301 ◽  
Author(s):  
Dijiong  Wu ◽  
Keding Shao ◽  
Qihao Zhou ◽  
Jie Sun ◽  
Ziqi Wang ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Fusion Protein ◽  
Cell Lines ◽  
Mrna Level ◽  
In Vivo Studies ◽  
Proteolytic Degradation ◽  
Induced Differentiation ◽  
Fluorescent Substrate

Background/Aims: Although the cure rate of acute promyelocytic leukemia (APL) has exceeded 90%, the relapse/refractory APL that resistant to all-trans retinoic acid (ATRA) or ATO was still serious concern. Matrine (MAT) could improve the differentiation ability of ATRA-resistant APL cells. This study aimed to explore how the APL-specific fusion protein was degraded in ATRA-resistant APL with the application of MAT and ATRA. Methods: ATRA-sensitive (NB4) and ATRA-resistant (NB4-LR1) cell lines were used. Nitroblue tetrazolium reduction assay and flow cytometry were used to detect the differentiation ability. The activity of ubiquitin-proteasome and autophagy-mediated pathways in both cells treated with ATRA with or without MAT were compared in protein and mRNA level (Western blot analysis, qRT-PCR), the Fluorescent substrate Suc-LLVY-AMC detection was used to detect the activity of proteasome, and electron microscope for observing autophagosome. MG 132(proteasome inhibitor), rapamycin (autophagy activator), hydroxychloroquine (lysosomal inhibitor) and STI571 [retinoic acid receptor alpha (RARα) ubiquitin stabilizer] were used as positive controls. The effect of MAT was observed in vivo using xenografts. Results: MAT improved the sensitivity of NB4-LR1cells to ATRA treatment, which was consistent with the expression of PML-RARα fusion protein. MAT promoted the ubiquitylation level in NB4-LR1. MG 132 induced the decrease in RARα in both cell lines, and hampered the differentiation of NB4 cells. MAT also promoted the autophagy in NB4-LR1 cells, with an increase in microtubule-associated protein 1 light chain3 (LC3)-II and LC3-II/LC3-I ratio and exhaustion of P62. The expression of LC3II increased significantly in the MAT and ATRA + MAT groups in combination with lysosomal inhibitors. A similar phenomenon was observed in mouse xenografts. MAT induced apoptosis and differentiation. Conclusions: Autophagy and ubiquitin-mediated proteolytic degradation of PML/RARα fusion protein are crucial in MAT-induced differentiation sensitivity recovery of NB4-LR1 cells.

scholarly journals Characterization of calcium- and integrin-binding protein 1 (CIB1) knockout platelets: Potential compensation by CIB family members

2008 ◽  
Vol 100 (05) ◽  
pp. 847-856 ◽  
Author(s):  
Brenda R. Temple ◽  
Holly R. Gentry ◽  
Jan C. DeNofrio ◽  
Weiping Yuan ◽  
Leslie V. Parise
Keyword(s):  
Thrombus Formation ◽  
Mrna Level ◽  
Family Members ◽  
Cytoplasmic Tail ◽  
Binding Pocket ◽  
Vitro Binding ◽  
Cytoplasmic Tails ◽  
Hydrophobic Binding

SummaryPlatelet aggregation requires activation of the αIIbβ3 integrin,an event regulated by the integrin cytoplasmic tails. CIB1 binds to the cytoplasmic tail of the integrin αIIb subunit. Previous overexpression and knockdown studies in murine megakaryocytes demonstrated that CIB1 inhibits integrin αIIbβ3 activation.Here we analyzed Cib1-/- mice to determine the function of CIB1 in platelets in vitro and in vivo. We found that although these mice had no overt platelet phenotype, mRNA level of CIB1 homolog CIB3 was increased in Cib1-/- megakaryocytes. In vitro binding experiments showed that recombinant CIB1, -2 and -3 bound specifically to an αIIb cytoplasmic tail peptide. Subsequent protein modeling experiments indicated that CIBs 1–3 each have a highly conserved hydrophobic binding pocket. Therefore, the potential exists for compensation for the loss of CIB1 by these CIB family members, thereby preventing pathologic thrombus formation in Cib1-/- mice.

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