scholarly journals Bunyamwera Orthobunyavirus S-Segment Untranslated Regions Mediate Poly(A) Tail-Independent Translation

2009 ◽  
Vol 83 (8) ◽  
pp. 3637-3646 ◽  
Author(s):  
Gjon Blakqori ◽  
Ingeborg van Knippenberg ◽  
Richard M. Elliott
Keyword(s):  
Rna Stability ◽  
Initiation Factor ◽  
Untranslated Regions ◽  
Luciferase Reporter ◽  
Translation Efficiency ◽  
Luciferase Reporter Gene ◽  
Viral Mrnas ◽  
Nuclear Retention ◽  
Eukaryotic Mrnas ◽  
Independent Process

ABSTRACT The mRNAs of Bunyamwera virus (BUNV), the prototype of the Bunyaviridae family, possess a 5′ cap structure but lack a 3′ poly(A) tail, a common feature of eukaryotic mRNAs that greatly enhances translation efficiency. Viral mRNAs also contain untranslated regions (UTRs) that flank the coding sequence. Using model virus-like mRNAs that harbor the Renilla luciferase reporter gene, we found that the 3′ UTR of the BUNV small-segment mRNA mediated efficient translation in the absence of a poly(A) tail. Viral UTRs did not increase RNA stability, and polyadenylation did not significantly enhance reporter activity. Translation of virus-like mRNAs in transfected cells was unaffected by knockdown of poly(A)-binding protein (PABP) but was markedly reduced by depletion of eukaryotic initiation factor 4G, suggesting a PABP-independent process for translation initiation. In BUNV-infected cells, translation of polyadenylated but not virus-like mRNAs was inhibited. Furthermore, we demonstrate that the viral nucleocapsid protein binds to, and colocalizes with, PABP in the cytoplasm early in infection, followed by nuclear retention of PABP. Our results suggest that BUNV corrupts PABP function in order to inhibit translation of polyadenylated cellular mRNAs while its own mRNAs are translated in a PABP-independent process.

Analysis of plant mRNA upstream open reading frames

2005 ◽  
Vol 2 (1) ◽  
pp. 59-66
Author(s):  
Jin Yong-Feng ◽  
Jin Hui-Qing ◽  
Zhou Ping ◽  
Bian Teng-Fei
Keyword(s):  
Plant Species ◽  
Open Reading Frames ◽  
Untranslated Regions ◽  
Translation Efficiency ◽  
Consensus Sequences ◽  
Codon Context ◽  
Eukaryotic Mrnas ◽  
Upstream Open Reading Frames ◽  
Regulatory Functions ◽  
Reading Frames

AbstractUpstream open reading frames (uORFs) in 5′-untranslated regions (5′-UTRs) of eukaryotic mRNAs play an important role in translation efficiency. Computational analysis of the upstream ATG (uATG) and uORFs of 5′-UTRs of plant mRNAs, adopted from the nucleotide sequence databank, was carried out. Statistical analysis revealed that up to 18% of 5′-UTRs contain uATG, which is much higher than the earlier estimate. Among them, about 50% of the genes have one uATG and nearly 20% of them have two uATGs. About 85% of uORFs are non-overlapping. Thirty per cent of uORF peptides comprise 1–5 aa, and about 80% of uORFs fall in the range of below 20 aa. Sequences flanking the uATG codon differ strikingly from the functional initiation codon and the uATG triplet is more frequently located in a non-optimal context. Consensus sequences of the ATG codon context of mRNA with and without uATG are similar, whereas the ATG codon context of mRNA without uATG is more frequently located in an optimal context than is mRNA with uATG. Most mRNAs with uATGs are possibly related to regulatory functions. In addition, most mRNA uORFs have no similarity between plant species whereas sequences of a few uORFs are highly conserved. For example, mRNA uORFs encoding S-adenosyl-l-methionine decarboxylase (AdoMetDC) share 75–100% homology between plant species, which is much more conserved than AdoMetDC protein.

scholarly journals N6-Methyladenosine Methyltransferase METTL14-Mediated Autophagy in Malignant Development of Oral Squamous Cell Carcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Fang Wang ◽  
Yue Zhu ◽  
Hongshi Cai ◽  
Jianfeng Liang ◽  
Wenjin Wang ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Oral Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Luciferase Reporter ◽  
Clinical Samples ◽  
Translation Efficiency ◽  
Rna Methylation

N6-methyladenosine (m6A) is the most abundant internal mRNA modification in eukaryotes and is related to stability, localization, or translation efficiency in tumorigenesis. Autophagy plays an important role in the occurrence and development of tumours. However, the relationship between m6A and autophagy remains unclear. In this study, we used a rapamycin-induced autophagy model of oral squamous cell carcinoma (OSCC) cells, and observed increased m6A RNA methylation. When autophagy was activated, the methyltransferase-like 14 (METTL14) expression was upregulated and influenced the proliferation, migration, and invasiveness of OSCC cells. Through meRIP-seq and RNA-seq analysis, we found that METTL14 directly combined with eukaryotic translation initiation factor gamma 1 (eIF4G1) mRNA and decreased its RNA stability. According to the dual-luciferase reporter and mutagenesis assay, the mutated site 1 of exon 11 of eIF4G1 is the key target of METTL14. Knockdown of the main m6A binding protein YTHDF2 may rescue the shortened half-life of eIF4G1 mRNA induced by METTL14 overexpression. Furthermore, an in vivo tumour xenograft model confirmed that a high METTL14 expression can effectively reduce OSCC growth. Additionally, using clinical samples, we found that patients with advanced or moderately/poorly differentiated tumours exhibited lower METTL14 levels. Taken together, our results revealed that METTL14 mediated eIF4G1 expression via m6A modification and regulated autophagy levels and biological functions in OSCC. Our findings not only expand our understanding of the correlation between autophagy and RNA methylation in tumorigenesis but also present an opportunity to develop new therapeutic options.

scholarly journals Regulation of Tacaribe Mammarenavirus Translation: Positive 5′ and Negative 3′ Elements and Role of Key Cellular Factors

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Sabrina Foscaldi ◽  
Alejandra D'Antuono ◽  
María Gabriela Noval ◽  
Gonzalo de Prat Gay ◽  
Luis Scolaro ◽  
...  
Keyword(s):  
New World ◽  
Matrix Protein ◽  
Mrna Translation ◽  
Initiation Factor ◽  
Translation Efficiency ◽  
Protein Z ◽  
Viral Mrnas ◽  
Tacaribe Virus ◽  
A Cell ◽  
The Impact

ABSTRACT Mammarenaviruses are enveloped viruses with a bisegmented negative-stranded RNA genome that encodes the nucleocapsid protein (NP), the envelope glycoprotein precursor (GPC), the RNA polymerase (L), and a RING matrix protein (Z). Viral proteins are synthesized from subgenomic mRNAs bearing a capped 5′ untranslated region (UTR) and lacking 3′ poly(A) tail. We analyzed the translation strategy of Tacaribe virus (TCRV), a prototype of the New World mammarenaviruses. A virus-like transcript that carries a reporter gene in place of the NP open reading frame and transcripts bearing modified 5′ and/or 3′ UTR were evaluated in a cell-based translation assay. We found that the presence of the cap structure at the 5′ end dramatically increases translation efficiency and that the viral 5′ UTR comprises stimulatory signals while the 3′ UTR,specifically the presence of a terminal C+G-rich sequence and/or a stem-loop structure, down-modulates translation. Additionally, translation was profoundly reduced in eukaryotic initiation factor (eIF) 4G-inactivated cells, whereas depletion of intracellular levels of eIF4E had less impact on virus-like mRNA translation than on a cell-like transcript. Translation efficiency was independent of NP expression or TCRV infection. Our results indicate that TCRV mRNAs are translated using a cap-dependent mechanism, whose efficiency relies on the interplay between stimulatory signals in the 5′ UTR and a negative modulatory element in the 3′ UTR. The low dependence on eIF4E suggests that viral mRNAs may engage yet-unknown noncanonical host factors for a cap-dependent initiation mechanism. IMPORTANCE Several members of the Arenaviridae family cause serious hemorrhagic fevers in humans. In the present report, we describe the mechanism by which Tacaribe virus, a prototypic nonpathogenic New World mammarenavirus, regulates viral mRNA translation. Our results highlight the impact of untranslated sequences and key host translation factors on this process. We propose a model that explains how viral mRNAs outcompete cellular mRNAs for the translation machinery. A better understanding of the mechanism of translation regulation of this virus can provide the bases for the rational design of new antiviral tools directed to pathogenic arenaviruses.

scholarly journals Down-regulation of lncRNA UCA1 enhances radiosensitivity in prostate cancer by suppressing EIF4G1 expression via sponging miR-331-3p

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Minhua Hu ◽  
Jincheng Yang
Keyword(s):  
Prostate Cancer ◽  
Noncoding Rna ◽  
Underlying Mechanism ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Western Blot Assay ◽  
Eukaryotic Translation ◽  
Gene Assay

Abstract Background We aimed to explore the role of long noncoding RNA urothelial carcinoma-associated 1 (lncRNA UCA1) and its underlying mechanism in the radioresistance of prostate cancer (PCa). Methods QRT-PCR was conducted to measure the expression of UCA1, microRNA-331-3p (miR-331-3p) and eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) in PCa tissues and cells. The relative protein level was determined by western blot assay. Cell proliferation and apoptosis were detected by MTT, colony formation assay, and flow cytometry, respectively. The target interaction between miR-331-3p and UCA1 or EIF4G1 was predicted through bioinformatics analysis, and verified by dual-luciferase reporter gene assay system. Results The high levels of UCA1 and EIF4G1 as well as the low level of miR-331-3p were observed in PCa tissues and cell lines. UCA1 and EIF4G1 expression were significantly upregulated by Gy radiation treatement. UCA1 or EIF4G1 knockdown repressed cell growth and enhanced cell apoptosis in 22RV1 and DU145 cells under radiation. Moreover, overexpression of EIF4G1 abolished UCA1 knockdown-induced effect on 6 Gy irradiated PCa cells. UCA1 sponged miR-331-3p to regulate EIF4G1 expression. Conclusions LncRNA UCA1 deletion suppressed the radioresistance to PCa by suppressing EIF4G1 expression via miR-331-3p. UCA1 acted as a potential regulator of radioresistance of PCa, providing a promising therapeutic target for PCa.

Influence of chlorophyll and tannins in plant extracts on cell-based luciferase reporter gene assays

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
S Vogl ◽  
P Picker ◽  
N Fakhrudin ◽  
A Atanasov ◽  
E Heiß ◽  
...  
Keyword(s):  
Reporter Gene ◽  
Plant Extracts ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Reporter Gene Assays

Post-Transcriptional Regulation of Cardiac Sarcomere Protein Titin Through 3’ Untranslated Regions

2013 ◽  
Vol 9 ◽  
Author(s):  
Tara A Shrout
Keyword(s):  
Gene Expression ◽  
Transcriptional Control ◽  
Striated Muscle ◽  
Binding Capacity ◽  
Structural Features ◽  
Neonatal Rat ◽  
Regulatory Control ◽  
Untranslated Regions ◽  
Luciferase Reporter ◽  
Regulatory Effects

Titin is the largest known protein in the human body, and forms the backbone of all striated muscle sarcomeres. The elastic nature of titin is an important component of muscle compliance and functionality. A significant amount of energy is expended to synthesize titin, thus we postulate that titin gene expression is under strict regulatory control in order to conserve cellular resources. In general, gene expression is mediated in part by post-transcriptional control elements located within the 5’ and 3’ untranslated regions (UTRs) of mature mRNA. The 3’UTR in particular contains structural features that affect binding capacity to other RNA components, such as MicroRNA, which control mRNA localization, translation, and degradation. The degree and significance of the regulatory effects mediated by two determined variants of titin’s 3’ UTR were evaluated in Neonatal Rat Ventricular Myocyte and Human Embryonic Kidney cell lines. Recombinant plasmids to transfect these cells lines were engineered by insertion of the variant titin 3’UTR 431- and 1047-base pairs sequences into luciferase reporter vectors. Expression due to an unaltered reporter vector served as the control. Quantitative changes in luciferase activity due to the recombinants proportionally represented the effect titin’s respective 3’UTR conferred on downstream post-transcriptional expression relative to the control. The effect due to titin’s shorter 3’UTR sequence was inconclusive; however, results illustrated that titin’s longer 3’UTR sequence caused a 35 percent decrease in protein expression. Secondary structural analysis of the two sequences revealed differential folding patterns that affect the stability and degree of MicroRNA-binding within titin’s variant 3’UTR sequences.

Investigation of Targeting Relationship between Micro-Rna-22 and Vegfr3 in Lung Squamous Cell Carcinoma

2020 ◽  
Vol 23 ◽  
Author(s):  
Zheng Dong ◽  
Qing-Hua Xu ◽  
Yuan-Bin Zhu ◽  
Yong-Feng Wang ◽  
Jie Xiong ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Lung Squamous Cell Carcinoma ◽  
Luciferase Reporter ◽  
Control Group ◽  
Vascular Endothelial ◽  
Luciferase Reporter Gene ◽  
Endothelial Growth Factor

Aims : The present study explored the clinical significance of microRNA-22 (miR-22) expression in lung squamous cell carcinoma and to explore the targeting relationship with vascular endothelial growth factor receptor 3 (VEGFR3). Methods: A total of 49 patients with lung squamous cell carcinoma who underwent surgical treatment was selected. The expression of miR-22 was detected by fluorescence quantitative real-time PCR (qPCR), the expression of VEGFR3 was detected by Western blotting assays, and D240 labeled microlymphatic vessels density (MLVD) was detected immunohistochemistry (IHC). Lung squamous cell carcinoma cell line SK-MES-1 was selected and the targeting relationship between miR-22 and VEGFR3 was analyzed by double luciferase reporter gene assay. Western blotting assays were used to detect the expression of vascular endothelial growth factor-D (VEGF-D) and D240 in the blank control group, empty vector transfection group, miR-22 transfection group, miR-22 and VEGFR3 co-transfection group. Results: The expression range of miR-22 in lung squamous cell carcinoma was 0.8-3.5. The expression of miR-22 in lung squamous cell carcinoma was significantly different by tumor maximum diameter, lymph node metastasis, vascular invasion and TNM stage. The expression of miR-22 was linked to survival time. There was a negative correlation between miR-22 and VEGFR3, miR-22 and MLVD. Double luciferase reporter gene assays showed that miR-22 reduced the luciferase activity of pGL3-VEGFR3-WT transfected cells. Compared with the control group, the expression of VEGF-D and D2-40 in the miR-22 transfection group was significantly decreased. However, VEGF-D and D240 in the miR-22 and VEGFR3 cotransfection group reversed the changes. Conclusion: We assumed that the abnormal expression of miR-22 in lung squamous cell carcinoma may be involved in the development and progression of lung squamous cell carcinoma. MiR-22 negatively regulated the target gene VEGFR3 to mediate lymphangiogenesis. The expression of miR-22 may also be linked to the prognosis of the disease.

Benzisothiazolone Derivatives Exhibit Cytotoxicity in Hodgkin’s Lymphoma Cells through NF-κB Inhibition and are Synergistic with Doxorubicin and Etoposide

2020 ◽  
Vol 20 (6) ◽  
pp. 715-723
Author(s):  
Natarajan Nandakumar ◽  
Pushparathinam Gopinath ◽  
Jacob Gopas ◽  
Kannoth M. Muraleedharan
Keyword(s):  
Synergistic Effect ◽  
Hodgkin’S Lymphoma ◽  
A549 Cells ◽  
Hodgkin's Lymphoma ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Lymphoma Cells ◽  
Nuclear Extracts ◽  
Gene Assay

Background: The authors investigated the NF-κB inhibitory role of three Benzisothiazolone (BIT) derivatives (1, 2 and 3) in Hodgkin’s Lymphoma cells (L428) which constitutively express activated NF-κB. All three compounds showed dose-dependent NF-κB inhibition (78.3, 70.7 and 34.6%) in the luciferase reporter gene assay and were found cytotoxic at IC50 values of 3.3μg/ml, 4.35μg/ml and 13.8μg/ml, respectively by the XTT assay. BIT 1and BIT 2 (but not BIT 3) suppressed both NF-κB subunits p50 and p65 in cytoplasmic and nuclear extracts in a concentration-dependent manner. Furthermore, BIT 1 showed a moderate synergistic effect with the standard chemotherapy drugs etoposide and doxorubicin, whereas BIT 2 and 3 showed a moderate additive effect to antagonistic effect. Cisplatin exhibited an antagonist effect on all the compounds tested under various concentrations, except in the case of 1.56μg/ml of BIT 3 with 0.156μg/ml of cisplatin. The compounds also inhibited the migration of adherent human lung adenocarcinoma cells (A549) in vitro. We conclude that especially BIT 1 and BIT 2 have in vitro anti-inflammatory and anti-cancer activities, which can be further investigated for future potential therapeutic use. Methods: Inspired by the electrophilic sulfur in Nuphar alkaloids, monomeric and dimeric benzisothiazolones were synthesized from dithiodibenzoic acid and their NF-κB inhibitory role was explored. NF-κB inhibition and cytotoxicity of the synthesized derivatives were studied using luciferase reporter gene assay and XTTassay. Immunocytochemistry studies were performed using L428 cells. Cell migration assay was conducted using the A549 cell line. L428 cells were used to conduct combination studies and the results were plotted using CompuSyn software. Results: Benzisothiazolone derivatives exhibited cytotoxicity in Hodgkin’s Lymphoma cells through NF-κB inhibition. Potent compounds showed suppression of both NF-κB subunits p50 and p65 in a concentrationdependent manner, both in cytoplasmic and nuclear extracts. Combination studies suggest that benzisothiazolone derivatives possess a synergistic effect with etoposide and doxorubicin. Furthermore, the compounds also inhibited the migration of A549 cells. Conclusion: Benzisothiazolones bearing one or two electrophilic sulfur atoms as part of the heterocyclic framework exhibited cytotoxicity in Hodgkin’s Lymphoma cells through NF-κB inhibition. In addition, these derivatives also exhibited a synergistic effect with etoposide and doxorubicin along with the ability to inhibit the migration of A549 cells. Our study suggests that BIT-based new chemical entities could lead to potential anticancer agents.

scholarly journals MiR-326 mediates malignant biological behaviors of lung adenocarcinoma by targeting ZEB1

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110093
Author(s):  
Mingxin Liu ◽  
Hong Wu ◽  
Yiqiang Liu ◽  
Yan Tan ◽  
Songtao Wang ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Cell Lines ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Invasion And Migration ◽  
Transwell Invasion Assay ◽  
Enhancer Binding Protein ◽  
Adenocarcinoma Cells ◽  
And Migration ◽  
Related Proteins

MiR-326 functions as an antioncogene in the several types of cancer. However, the underling mechanisms through which miRNA-326 regulates the anti-carcinogenesis of lung adenocarcinoma have remained elusive. The aim of this study was to explore the role and regulatory mechanism of miR-326 in cell proliferation, invasion, migration and apoptosis in lung adenocarcinoma. Quantitative real-time PCR (qRT-PCR) was used to detect the expression pattern of miR-326 in human bronchial epithelial cells (HBES-2B), 4 kinds of lung adenocarcinoma cell lines (H23, H1975, H2228, H2085) and 20 lung adenocarcinoma tissues. Then, H23 cells were infected with miR-326 mimics, miR-326 inhibitors and si-ZEB1 to build up-regulated miR-326 cell lines, down-regulated ZEB1(zinc-finger-enhancer binding protein 1)cell lines, simultaneous down-regulated ZEB1 and miR-326 cell lines. Moreover, CCK-8 assay, transwell invasion assay, wound healing assay and flow cytometry assay were employed to examine the effects of miR-326 and ZEB1 on the proliferation, invasion, migration and apoptosis abilities of H23 cells. Western blot was performed to explore the effects of miR-326 and ZEB1 on the expression of invasion and migration related proteins N-cadherin, E-cadherin, MMP7, MMP13, SLUG and apoptotic proteins PARP, BAX. On the mechanism, a dual-luciferase reporter gene was used to measure the target relationship between miR-326 and ZEB1. MiR-326 expression was significantly downregulated in lung adenocarcinoma tissues and cells. Overexpression of miR-326 significantly inhibited the malignant behaviors of H23 cells. Mechanically, luciferase reporter assay showed that ZEB1 was a direct target of miR-326. MiR-326 mimic downregulated the expression of ZEB1. Furthermore, knocking down ZEB1 strongly inhibited the proliferation, invasion and migration of H23 cells but promoted apoptosis. MiR-326 could target ZEB1 to inhibit the proliferation, invasion and migration of lung adenocarcinoma cells and promote apoptosis, which is a potential therapeutic target for lung adenocarcinoma.

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