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1.
Nat Commun ; 15(1): 5748, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38982041

ABSTRACT

Autoimmune thyroid disease (AITD) is a common autoimmune disease. In a GWAS meta-analysis of 110,945 cases and 1,084,290 controls, 290 sequence variants at 225 loci are associated with AITD. Of these variants, 115 are previously unreported. Multiomics analysis yields 235 candidate genes outside the MHC-region and the findings highlight the importance of genes involved in T-cell regulation. A rare 5'-UTR variant (rs781745126-T, MAF = 0.13% in Iceland) in LAG3 has the largest effect (OR = 3.42, P = 2.2 × 10-16) and generates a novel start codon for an open reading frame upstream of the canonical protein translation initiation site. rs781745126-T reduces mRNA and surface expression of the inhibitory immune checkpoint LAG-3 co-receptor on activated lymphocyte subsets and halves LAG-3 levels in plasma among heterozygotes. All three homozygous carriers of rs781745126-T have AITD, of whom one also has two other T-cell mediated diseases, that is vitiligo and type 1 diabetes. rs781745126-T associates nominally with vitiligo (OR = 5.1, P = 6.5 × 10-3) but not with type 1 diabetes. Thus, the effect of rs781745126-T is akin to drugs that inhibit LAG-3, which unleash immune responses and can have thyroid dysfunction and vitiligo as adverse events. This illustrates how a multiomics approach can reveal potential drug targets and safety concerns.


Subject(s)
Antigens, CD , Codon, Initiator , Genetic Predisposition to Disease , Lymphocyte Activation Gene 3 Protein , Humans , Codon, Initiator/genetics , Antigens, CD/genetics , Antigens, CD/metabolism , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/immunology , Female , Polymorphism, Single Nucleotide , Vitiligo/genetics , Male , Genome-Wide Association Study , Thyroiditis, Autoimmune/genetics , 5' Untranslated Regions/genetics , Case-Control Studies , Iceland , Adult
2.
Nat Commun ; 15(1): 5284, 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38902240

ABSTRACT

mRNA therapeutics are revolutionizing the pharmaceutical industry, but methods to optimize the primary sequence for increased expression are still lacking. Here, we design 5'UTRs for efficient mRNA translation using deep learning. We perform polysome profiling of fully or partially randomized 5'UTR libraries in three cell types and find that UTR performance is highly correlated across cell types. We train models on our datasets and use them to guide the design of high-performing 5'UTRs using gradient descent and generative neural networks. We experimentally test designed 5'UTRs with mRNA encoding megaTALTM gene editing enzymes for two different gene targets and in two different cell lines. We find that the designed 5'UTRs support strong gene editing activity. Editing efficiency is correlated between cell types and gene targets, although the best performing UTR was specific to one cargo and cell type. Our results highlight the potential of model-based sequence design for mRNA therapeutics.


Subject(s)
5' Untranslated Regions , Deep Learning , Gene Editing , RNA, Messenger , RNA, Messenger/genetics , RNA, Messenger/metabolism , 5' Untranslated Regions/genetics , Humans , Gene Editing/methods , Polyribosomes/metabolism , Cell Line , HEK293 Cells , Protein Biosynthesis
4.
Retrovirology ; 21(1): 12, 2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38886829

ABSTRACT

An essential regulatory hub for retroviral replication events, the 5' untranslated region (UTR) encodes an ensemble of cis-acting replication elements that overlap in a logical manner to carry out divergent RNA activities in cells and in virions. The primer binding site (PBS) and primer activation sequence initiate the reverse transcription process in virions, yet overlap with structural elements that regulate expression of the complex viral proteome. PBS-segment also encompasses the attachment site for Integrase to cut and paste the 3' long terminal repeat into the host chromosome to form the provirus and purine residues necessary to execute the precise stoichiometry of genome-length transcripts and spliced viral RNAs. Recent genetic mapping, cofactor affinity experiments, NMR and SAXS have elucidated that the HIV-1 PBS-segment folds into a three-way junction structure. The three-way junction structure is recognized by the host's nuclear RNA helicase A/DHX9 (RHA). RHA tethers host trimethyl guanosine synthase 1 to the Rev/Rev responsive element (RRE)-containing RNAs for m7-guanosine Cap hyper methylation that bolsters virion infectivity significantly. The HIV-1 trimethylated (TMG) Cap licenses specialized translation of virion proteins under conditions that repress translation of the regulatory proteins. Clearly host-adaption and RNA shapeshifting comprise the fundamental basis for PBS-segment orchestrating both reverse transcription of virion RNA and the nuclear modification of m7G-Cap for biphasic translation of the complex viral proteome. These recent observations, which have exposed even greater complexity of retroviral RNA biology than previously established, are the impetus for this article. Basic research to fully comprehend the marriage of PBS-segment structures and host RNA binding proteins that carry out retroviral early and late replication events is likely to expose an immutable virus-specific therapeutic target to attenuate retrovirus proliferation.


Subject(s)
5' Untranslated Regions , HIV-1 , RNA, Viral , Virus Replication , RNA, Viral/genetics , RNA, Viral/metabolism , Humans , HIV-1/physiology , HIV-1/genetics , Binding Sites , Gene Expression Regulation, Viral , Reverse Transcription , Retroviridae/physiology , Retroviridae/genetics
5.
Cell Rep ; 43(6): 114330, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38865241

ABSTRACT

The human genome has many short tandem repeats, yet the normal functions of these repeats are unclear. The 5' untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene contains polymorphic CGG repeats, the length of which has differing effects on FMR1 expression and human health, including the neurodevelopmental disorder fragile X syndrome. We deleted the CGG repeats in the FMR1 gene (0CGG) in human stem cells and examined the effects on differentiated neurons. 0CGG neurons have altered subcellular localization of FMR1 mRNA and protein, and differential expression of cellular stress proteins compared with neurons with normal repeats (31CGG). In addition, 0CGG neurons have altered responses to glucocorticoid receptor (GR) activation, including FMR1 mRNA localization, GR chaperone HSP90α expression, GR localization, and cellular stress protein levels. Therefore, the CGG repeats in the FMR1 gene are important for the homeostatic responses of neurons to stress signals.


Subject(s)
Fragile X Mental Retardation Protein , Neurons , RNA, Messenger , Humans , Fragile X Mental Retardation Protein/metabolism , Fragile X Mental Retardation Protein/genetics , Neurons/metabolism , RNA, Messenger/metabolism , RNA, Messenger/genetics , Receptors, Glucocorticoid/metabolism , Receptors, Glucocorticoid/genetics , Stress, Physiological/genetics , 5' Untranslated Regions/genetics , HSP90 Heat-Shock Proteins/metabolism , HSP90 Heat-Shock Proteins/genetics , Trinucleotide Repeats/genetics , Trinucleotide Repeat Expansion/genetics
6.
Biochem Biophys Res Commun ; 725: 150252, 2024 Sep 17.
Article in English | MEDLINE | ID: mdl-38878758

ABSTRACT

Reverse transcription of human immunodeficiency virus type 1 (HIV-1) initiates from the 3' end of human tRNALys3. The primer tRNALys3 is selectively packaged into the virus in the form of a complex with human lysyl-tRNA synthetase (LysRS). To facilitate reverse transcription initiation, part of the 5' leader (5'L) of HIV-1 genomic RNA (gRNA) evolves a tRNA anticodon-like element (TLE), which binds LysRS and releases tRNALys3 for primer annealing and reverse transcription initiation. Although TLE has been identified as a key element in 5'L responsible for LysRS binding, how the conformations and various hairpin structures of 5'L regulate 5'L-LysRS interaction is not fully understood. Here, these factors have been individually investigated using direct and competitive fluorescence anisotropy binding experiments. Our data showed that the conformation of 5'L significantly influences its binding affinity with LysRS. The 5'L conformation favoring gRNA dimerization and packaging exhibits much weaker binding affinity with LysRS compared to the alternative 5'L conformation that is not selected for packaging. Additionally, dimerization of 5'L impairs LysRS-5'L interaction. Furthermore, among various regions of 5'L, both the primer binding site/TLE domain and the stem-loop 3 are important for LysRS interaction, whereas the dimerization initiation site and the splicing donor plays a minor role. In contrast, the presence of the transacting responsive and the polyadenylation signal hairpins slightly inhibit LysRS binding. These findings reveal that the conformation and various regions of the 5'L of HIV-1 genome regulate its interaction with human LysRS and the reverse transcription primer release process.


Subject(s)
Genome, Viral , HIV-1 , Lysine-tRNA Ligase , Nucleic Acid Conformation , Reverse Transcription , Lysine-tRNA Ligase/metabolism , Lysine-tRNA Ligase/chemistry , Lysine-tRNA Ligase/genetics , Humans , HIV-1/genetics , HIV-1/enzymology , RNA, Viral/metabolism , RNA, Viral/chemistry , RNA, Viral/genetics , 5' Untranslated Regions , Protein Binding
7.
Mol Cell ; 84(11): 2119-2134.e5, 2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38848691

ABSTRACT

Protein synthesis is metabolically costly and must be tightly coordinated with changing cellular needs and nutrient availability. The cap-binding protein eIF4E makes the earliest contact between mRNAs and the translation machinery, offering a key regulatory nexus. We acutely depleted this essential protein and found surprisingly modest effects on cell growth and recovery of protein synthesis. Paradoxically, impaired protein biosynthesis upregulated genes involved in the catabolism of aromatic amino acids simultaneously with the induction of the amino acid biosynthetic regulon driven by the integrated stress response factor GCN4. We further identified the translational control of Pho85 cyclin 5 (PCL5), a negative regulator of Gcn4, that provides a consistent protein-to-mRNA ratio under varied translation environments. This regulation depended in part on a uniquely long poly(A) tract in the PCL5 5' UTR and poly(A) binding protein. Collectively, these results highlight how eIF4E connects protein synthesis to metabolic gene regulation, uncovering mechanisms controlling translation during environmental challenges.


Subject(s)
Amino Acids , Eukaryotic Initiation Factor-4E , Gene Expression Regulation, Fungal , Protein Biosynthesis , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Eukaryotic Initiation Factor-4E/metabolism , Eukaryotic Initiation Factor-4E/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Amino Acids/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , RNA, Messenger/metabolism , RNA, Messenger/genetics , 5' Untranslated Regions , Basic-Leucine Zipper Transcription Factors/metabolism , Basic-Leucine Zipper Transcription Factors/genetics , Cyclins/genetics , Cyclins/metabolism , Poly(A)-Binding Proteins/metabolism , Poly(A)-Binding Proteins/genetics
8.
J Exp Med ; 221(7)2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38861022

ABSTRACT

The IL-17 receptor adaptor molecule Act1, an RNA-binding protein, plays a critical role in IL-17-mediated cancer progression. Here, we report a novel mechanism of how IL-17/Act1 induces chemoresistance by modulating redox homeostasis through epitranscriptomic regulation of antioxidant RNA metabolism. Transcriptome-wide mapping of direct Act1-RNA interactions revealed that Act1 binds to the 5'UTR of antioxidant mRNAs and Wilms' tumor 1-associating protein (WTAP), a key regulator in m6A methyltransferase complex. Strikingly, Act1's binding sites are located in proximity to m6A modification sites, which allows Act1 to promote the recruitment of elF3G for cap-independent translation. Loss of Act1's RNA binding activity or Wtap knockdown abolished IL-17-induced m6A modification and translation of Wtap and antioxidant mRNAs, indicating a feedforward mechanism of the Act1-WTAP loop. We then developed antisense oligonucleotides (Wtap ASO) that specifically disrupt Act1's binding to Wtap mRNA, abolishing IL-17/Act1-WTAP-mediated antioxidant protein production during chemotherapy. Wtap ASO substantially increased the antitumor efficacy of cisplatin, demonstrating a potential therapeutic strategy for chemoresistance.


Subject(s)
Antioxidants , Drug Resistance, Neoplasm , Homeostasis , Oxidation-Reduction , Drug Resistance, Neoplasm/genetics , Humans , Antioxidants/metabolism , Antioxidants/pharmacology , Animals , Cell Line, Tumor , RNA, Messenger/metabolism , RNA, Messenger/genetics , Interleukin-17/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Mice , Cell Cycle Proteins/metabolism , Cell Cycle Proteins/genetics , Gene Expression Regulation, Neoplastic/drug effects , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/genetics , 5' Untranslated Regions , Cisplatin/pharmacology , RNA Splicing Factors
9.
Nat Commun ; 15(1): 4879, 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38849354

ABSTRACT

The mammalian neocortex comprises an enormous diversity regarding cell types, morphology, and connectivity. In this work, we discover a post-transcriptional mechanism of gene expression regulation, protein translation, as a determinant of cortical neuron identity. We find specific upregulation of protein synthesis in the progenitors of later-born neurons and show that translation rates and concomitantly protein half-lives are inherent features of cortical neuron subtypes. In a small molecule screening, we identify Ire1α as a regulator of Satb2 expression and neuronal polarity. In the developing brain, Ire1α regulates global translation rates, coordinates ribosome traffic, and the expression of eIF4A1. Furthermore, we demonstrate that the Satb2 mRNA translation requires eIF4A1 helicase activity towards its 5'-untranslated region. Altogether, we show that cortical neuron diversity is generated by mechanisms operating beyond gene transcription, with Ire1α-safeguarded proteostasis serving as an essential regulator of brain development.


Subject(s)
Matrix Attachment Region Binding Proteins , Neocortex , Neurons , Protein Biosynthesis , Protein Serine-Threonine Kinases , Animals , Neocortex/metabolism , Neocortex/cytology , Neocortex/embryology , Neurons/metabolism , Neurons/cytology , Mice , Protein Serine-Threonine Kinases/metabolism , Protein Serine-Threonine Kinases/genetics , Matrix Attachment Region Binding Proteins/metabolism , Matrix Attachment Region Binding Proteins/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Gene Expression Regulation, Developmental , Proteostasis , Neurogenesis/genetics , RNA, Messenger/metabolism , RNA, Messenger/genetics , 5' Untranslated Regions/genetics , Ribosomes/metabolism , Ribosomes/genetics , Humans , Endoribonucleases/metabolism , Endoribonucleases/genetics , Cell Differentiation/genetics
10.
Indian J Med Microbiol ; 49: 100601, 2024.
Article in English | MEDLINE | ID: mdl-38705277

ABSTRACT

PURPOSE: Acute Hemorrhagic conjunctivitis (AHC) is associated with CVA24v. Recently there was a severe outbreak of conjunctivitis in months of July and August 2023 in India. This study emphasizes the identification of the distinct mutations in the CVA24v strains, which were isolated during the AHC outbreak and could have potentially played a role in the high transmission of AHC in India during the 2023 outbreak. METHODS: A total of 71 conjunctivitis patients aged 1-75 years comprising 47 males and 24 females who attended Ophthalmology department of a tertiary care hospital of easternIndia were studied.RNA was extracted from all conjunctival swab samples and converted into cDNA. Subsequently, the viral 5' UTR was amplified and the PCR positive samples were subjected to sequencing. The newly isolated viral 5' UTR sequences were aligned with other worldwide sequences using the Clustal W tool to conduct mutational analysis. A phylogenetic tree was built using the MEGA software for viral genotype identification. RESULTS: All of the current outbreak strains belonged to genotype IV of CVA24v. The present outbreak strains formed a distinct clade in the phylogenetic tree and were different from previously reported Indian strains. Two persistent mutations, specifically in domain IV (T213C) and domain V (C475T), were exclusively detected within the internal ribosome entry site (IRES) of the 5' UTR of the current strains causing the outbreak. These two alterations have previously been shown to impact the virulence of another enterovirus (CV B3), but they have not been described in CVA24v until now. CONCLUSION: Finding of the present study highlights the possibility and the significance of the aforementioned two mutations in enhancing the transmissibility of the newer CVA24v strains. Hence, these two distinct mutations should be investigated further for developing antiviral therapies to combat future AHC outbreaks associated with CVA24v.


Subject(s)
Conjunctivitis, Acute Hemorrhagic , Disease Outbreaks , Enterovirus C, Human , Genotype , Phylogeny , Humans , Conjunctivitis, Acute Hemorrhagic/virology , Conjunctivitis, Acute Hemorrhagic/epidemiology , Female , Male , Adolescent , Child, Preschool , Adult , Child , Middle Aged , Young Adult , India/epidemiology , Aged , Infant , Enterovirus C, Human/genetics , Enterovirus C, Human/isolation & purification , Enterovirus C, Human/classification , 5' Untranslated Regions/genetics , RNA, Viral/genetics , Mutation , Coxsackievirus Infections/virology , Coxsackievirus Infections/epidemiology
11.
Mol Microbiol ; 121(6): 1217-1227, 2024 06.
Article in English | MEDLINE | ID: mdl-38725184

ABSTRACT

The hmuR operon encodes proteins for the uptake and utilization of heme as a nutritional iron source in Bradyrhizobium japonicum. The hmuR operon is transcriptionally activated by the Irr protein and is also positively controlled by HmuP by an unknown mechanism. An hmuP mutant does not express the hmuR operon genes nor does it grow on heme. Here, we show that hmuR expression from a heterologous promoter still requires hmuP, suggesting that HmuP does not regulate at the transcriptional level. Replacement of the 5' untranslated region (5'UTR) of an HmuP-independent gene with the hmuR 5'UTR conferred HmuP-dependent expression on that gene. Recombinant HmuP bound an HmuP-responsive RNA element (HPRE) within the hmuR 5'UTR. A 2 nt substitution predicted to destabilize the secondary structure of the HPRE abolished both HmuP binding activity in vitro and hmuR expression in cells. However, deletion of the HPRE partially restored hmuR expression in an hmuP mutant, and it rescued growth of the hmuP mutant on heme. These findings suggest that the HPRE is a negative regulatory RNA element that is suppressed when bound by HmuP to express the hmuR operon.


Subject(s)
5' Untranslated Regions , Bacterial Proteins , Bradyrhizobium , Gene Expression Regulation, Bacterial , Operon , RNA-Binding Proteins , Bradyrhizobium/genetics , Bradyrhizobium/metabolism , Operon/genetics , 5' Untranslated Regions/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/genetics , Heme/metabolism , Promoter Regions, Genetic , RNA, Bacterial/metabolism , RNA, Bacterial/genetics , Protein Binding
12.
Eur J Med Genet ; 69: 104946, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38705457

ABSTRACT

Germline MICAL1 defects have been rarely reported in patients with epilepsy and the genotype-phenotype association remains unclear. In this study, the patient was a 4.6 years old girl who presented with onset of recurrent focal seizures with onset at age 3.4 years. EEG showed abnormal δ-wave activity in the right central and middle temporal lobe. Trio WES showed a novel heterozygous variant c.-43-1G > A in the MICAL1 gene in the patient and her normal mother. Minigene verified two abnormal transcripts due to the mutation, which was predicted to interrupt 5'UTR structures of MICAL1. The patient was clinically diagnosed with benign childhood epilepsy with centrotemporal spike (BECTS). As far as we know, this is the first BECTS case with documented MICAL1 mutation. Novel MICAL1 variant c.-43-1G > A putatively interrupted MICAL1 translation by changing 5'UTR structures and, however, further functioning study is needed.


Subject(s)
Epilepsy , Humans , Female , Child, Preschool , Epilepsy/genetics , Epilepsy/pathology , RNA Splicing , 5' Untranslated Regions , Mutation
13.
Sci Rep ; 14(1): 11159, 2024 05 15.
Article in English | MEDLINE | ID: mdl-38750152

ABSTRACT

Hepatitis is a major public health issue, affecting 10-17 million people worldwide, with its prevalence continuously increasing. The Hepatitis C virus (HCV) is responsible for liver related diseases, which include liver cirrhosis, hepatocellular carcinoma, and chronic hepatitis. Pakistan is experiencing a serious rise in HCV cases. This study aimed to assess the prevalence and distribution of HCV genotypes in Sindh, Pakistan. Serum samples from HCV-positive patients were collected from various local hospitals in Sindh. These samples were first screened for HCV antibodies using ELISA. Samples that tested positive for HCV RNA underwent further genotyping through sequencing using the standard Sanger method. The genotypes were identified by comparing the sequences with those available in the National Center for Biotechnology Information (NCBI) database, and a phylogenetic tree was constructed. The phylogenetic analysis showed that all isolates in this study were clustered with genotypes 3a and 3b, except for one sequence that was clustered with genotype 1a. No isolates were found to be clustered with reference genomes of genotypes 2, 4, 5, 6, and 7 suggesting that genotype 3a is endemic in this region. The analyzed sequences demonstrated a 98% similarity with reference and isolated sequences. In summary, sequencing of the HCV 5' UTR essential for identifying the predominant genotype of HCV RNA in the Sindh region Further research on the distribution of HCV genotypes in other regions of Pakistan could aid in improving screening processes, identifying more effective treatment options, and developing suitable prevention strategies.


Subject(s)
Genotype , Hepacivirus , Hepatitis C , Phylogeny , Pakistan/epidemiology , Humans , Hepacivirus/genetics , Hepacivirus/isolation & purification , Hepacivirus/classification , Hepatitis C/epidemiology , Hepatitis C/virology , Female , Male , Adult , Prevalence , RNA, Viral/genetics , Middle Aged , 5' Untranslated Regions/genetics , Adolescent , Young Adult
14.
Biochemistry ; 63(10): 1235-1240, 2024 May 21.
Article in English | MEDLINE | ID: mdl-38718213

ABSTRACT

Nonstructural protein 1 (nsp1) of the severe acute respiratory syndrome coronavirus (SCOV1 and SCOV2) acts as a host shutoff protein by blocking the translation of host mRNAs and triggering their decay. Surprisingly, viral RNA, which resembles host mRNAs containing a 5'-cap and a 3'-poly(A) tail, escapes significant translation inhibition and RNA decay, aiding viral propagation. Current literature proposes that, in SCOV2, nsp1 binds the viral RNA leader sequence, and the interaction may serve to distinguish viral RNA from host mRNA. However, a direct binding between SCOV1 nsp1 and the corresponding RNA leader sequence has not been established yet. Here, we show that SCOV1 nsp1 binds to the SCOV1 RNA leader sequence but forms multiple complexes at a high concentration of nsp1. These complexes are marginally different from complexes formed with SCOV2 nsp1. Finally, mutations of the RNA stem-loop did not completely abolish RNA binding by nsp1, suggesting that an RNA secondary structure is more important for binding than the sequence itself. Understanding the nature of binding of nsp1 to viral RNA will allow us to understand how this viral protein selectively suppresses host gene expression.


Subject(s)
RNA, Viral , Viral Nonstructural Proteins , RNA, Viral/metabolism , RNA, Viral/genetics , RNA, Viral/chemistry , Viral Nonstructural Proteins/metabolism , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Protein Binding , Humans , Severe acute respiratory syndrome-related coronavirus/genetics , Severe acute respiratory syndrome-related coronavirus/metabolism , 5' Untranslated Regions , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , RNA-Dependent RNA Polymerase
15.
Nat Commun ; 15(1): 3963, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38729943

ABSTRACT

Translation initiation in bacteria is frequently regulated by various structures in the 5' untranslated region (5'UTR). Previously, we demonstrated that G-quadruplex (G4) formation in non-template DNA enhances transcription. In this study, we aim to explore how G4 formation in mRNA (RG4) at 5'UTR impacts translation using a T7-based in vitro translation system and in E. coli. We show that RG4 strongly promotes translation efficiency in a size-dependent manner. Additionally, inserting a hairpin upstream of the RG4 further enhances translation efficiency, reaching up to a 12-fold increase. We find that the RG4-dependent effect is not due to increased ribosome affinity, ribosome binding site accessibility, or mRNA stability. We propose a physical barrier model in which bulky structures in 5'UTR biases ribosome movement toward the downstream start codon, thereby increasing the translation output. This study provides biophysical insights into the regulatory role of 5'UTR structures in in vitro and bacterial translation, highlighting their potential applications in tuning gene expression.


Subject(s)
5' Untranslated Regions , Escherichia coli , G-Quadruplexes , Protein Biosynthesis , RNA, Messenger , Ribosomes , 5' Untranslated Regions/genetics , Escherichia coli/genetics , Escherichia coli/metabolism , Ribosomes/metabolism , Ribosomes/genetics , RNA, Messenger/metabolism , RNA, Messenger/genetics , Nucleic Acid Conformation , RNA Stability , Binding Sites
16.
Parasit Vectors ; 17(1): 238, 2024 May 27.
Article in English | MEDLINE | ID: mdl-38802937

ABSTRACT

BACKGROUND: Eukaryotic genes contain introns that are removed by the spliceosomal machinery during mRNA maturation. Introns impose a huge energetic burden on a cell; therefore, they must play an essential role in maintaining genome stability and/or regulating gene expression. Many genes (> 50%) in Plasmodium parasites contain predicted introns, including introns in 5' and 3' untranslated regions (UTR). However, the roles of UTR introns in the gene expression of malaria parasites remain unknown. METHODS: In this study, an episomal dual-luciferase assay was developed to evaluate gene expression driven by promoters with or without a 5'UTR intron from four Plasmodium yoelii genes. To investigate the effect of the 5'UTR intron on endogenous gene expression, the pytctp gene was tagged with 3xHA at the N-terminal of the coding region, and parasites with or without the 5'UTR intron were generated using the CRISPR/Cas9 system. RESULTS: We showed that promoters with 5'UTR introns had higher activities in driving gene expression than those without 5'UTR introns. The results were confirmed in recombinant parasites expressing an HA-tagged gene (pytctp) driven by promoter with or without 5'UTR intron. The enhancement of gene expression was intron size dependent, but not the DNA sequence, e.g. the longer the intron, the higher levels of expression. Similar results were observed when a promoter from one strain of P. yoelii was introduced into different parasite strains. Finally, the 5'UTR introns were alternatively spliced in different parasite development stages, suggesting an active mechanism employed by the parasites to regulate gene expression in various developmental stages. CONCLUSIONS: Plasmodium 5'UTR introns enhance gene expression in a size-dependent manner; the presence of alternatively spliced mRNAs in different parasite developmental stages suggests that alternative slicing of 5'UTR introns is one of the key mechanisms in regulating parasite gene expression and differentiation.


Subject(s)
5' Untranslated Regions , Introns , Plasmodium yoelii , Promoter Regions, Genetic , 5' Untranslated Regions/genetics , Introns/genetics , Plasmodium yoelii/genetics , Plasmodium yoelii/growth & development , Animals , Gene Expression , Mice , Gene Expression Regulation , CRISPR-Cas Systems
17.
Virol J ; 21(1): 114, 2024 May 22.
Article in English | MEDLINE | ID: mdl-38778344

ABSTRACT

BACKGROUND: EV71 is one of the important pathogens of Hand-foot-and-mouth disease (HFMD), which causes serious neurological symptoms. Several studies have speculated that there will be interaction between 5'UTR and 3D protein. However, whether 5'UTR interacts with the 3D protein in regulating virus replication has not been clarified. METHODS: Four 5'UTR mutation sites (nt88C/T, nt90-102-3C, nt157G/A and nt574T/A) and two 3D protein mutation sites (S37N and R142K) were mutated or co-mutated using virulent strains as templates. The replication of these mutant viruses and their effect on autophagy were determined. RESULTS: 5'UTR single-point mutant strains, except for EGFP-EV71(nt90-102-3C), triggered replication attenuation. The replication ability of them was weaker than that of the parent strain the virulent strain SDLY107 which is the fatal strain that can cause severe neurological complications. While the replication level of the co-mutant strains showed different characteristics. 5 co-mutant strains with interaction were screened: EGFP-EV71(S37N-nt88C/T), EGFP-EV71(S37N-nt574T/A), EGFP-EV71(R142K-nt574T/A), EGFP-EV71(R142K-nt88C/T), and EGFP-EV71(R142K-nt157G/A). The results showed that the high replicative strains significantly promoted the accumulation of autophagosomes in host cells and hindered the degradation of autolysosomes. The low replicative strains had a low ability to regulate the autophagy of host cells. In addition, the high replicative strains also significantly inhibited the phosphorylation of AKT and mTOR. CONCLUSIONS: EV71 5'UTR interacted with the 3D protein during virus replication. The co-mutation of S37N and nt88C/T, S37N and nt574T/ A, R142K and nt574T/A induced incomplete autophagy of host cells and promoted virus replication by inhibiting the autophagy pathway AKT-mTOR. The co-mutation of R142K and nt88C/T, and R142K and nt157G/A significantly reduced the inhibitory effect of EV71 on the AKT-mTOR pathway and reduced the replication ability of the virus.


Subject(s)
5' Untranslated Regions , Enterovirus A, Human , Proto-Oncogene Proteins c-akt , TOR Serine-Threonine Kinases , Virus Replication , Enterovirus A, Human/genetics , Enterovirus A, Human/physiology , Enterovirus A, Human/pathogenicity , 5' Untranslated Regions/genetics , Humans , TOR Serine-Threonine Kinases/metabolism , TOR Serine-Threonine Kinases/genetics , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-akt/genetics , Autophagy , Animals , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism , Signal Transduction , Chlorocebus aethiops , Mutation , Cell Line , Vero Cells
18.
Nucleic Acids Res ; 52(10): 6066-6078, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38738640

ABSTRACT

The Trans-Activator Receptor (TAR) RNA, located at the 5'-end untranslated region (5' UTR) of the human immunodeficiency virus type 1 (HIV-1), is pivotal in the virus's life cycle. As the initial functional domain, it folds during the transcription of viral mRNA. Although TAR's role in recruiting the Tat protein for trans-activation is established, the detailed kinetic mechanisms at play during early transcription, especially at points of temporary transcriptional pausing, remain elusive. Moreover, the precise physical processes of transcriptional pause and subsequent escape are not fully elucidated. This study focuses on the folding kinetics of TAR and the biological implications by integrating computer simulations of RNA folding during transcription with nuclear magnetic resonance (NMR) spectroscopy data. The findings reveal insights into the folding mechanism of a non-native intermediate that triggers transcriptional pause, along with different folding pathways leading to transcriptional pause and readthrough. The profiling of the cotranscriptional folding pathway and identification of kinetic structural intermediates reveal a novel mechanism for viral transcriptional regulation, which could pave the way for new antiviral drug designs targeting kinetic cotranscriptional folding pathways in viral RNAs.


Subject(s)
HIV Long Terminal Repeat , HIV-1 , RNA Folding , RNA, Viral , Transcription, Genetic , HIV-1/genetics , Kinetics , RNA, Viral/metabolism , RNA, Viral/chemistry , RNA, Viral/genetics , HIV Long Terminal Repeat/genetics , Nucleic Acid Conformation , Humans , 5' Untranslated Regions , Gene Expression Regulation, Viral , Magnetic Resonance Spectroscopy
19.
Arch Virol ; 169(6): 126, 2024 May 16.
Article in English | MEDLINE | ID: mdl-38753067

ABSTRACT

A novel mitovirus was identified in Fusarium oxysporum f. sp. melonis strain T-SD3 and designated as "Fusarium oxysporum mitovirus 3" (FoMV3). The virus was isolated from diseased muskmelon plants with the typical symptom of fusarium wilt. The complete genome of FoMV3 is 2269 nt in length with a predicted AU content of 61.40% and contains a single open reading frame (ORF) using the fungal mitochondrial genetic code. The ORF was predicted to encode a polypeptide of 679 amino acids (aa) containing a conserved RNA-dependent RNA polymerase (RdRp) domain with a molecular mass of 77.39 kDa, which contains six conserved motifs with the highly conserved GDD tripeptide in motif IV. The 5'-untranslated region (UTR) and 3'-UTR of FoMV3 were predicted to fold into stem-loop structures. BLASTp analysis revealed that the RdRp of FoMV3 shared the highest aa sequence identity (83.85%) with that of Fusarium asiaticum mitovirus 5 (FaMV5, a member of the family Mitoviridae) infecting F. asiaticum, the causal agent of wheat fusarium head blight. Phylogenetic analysis further suggested that FoMV3 is a new member of the genus Unuamitovirus within the family Mitoviridae. This is the first report of a new mitovirus associated with F. oxysporum f. sp. melonis.


Subject(s)
Fungal Viruses , Fusarium , Genome, Viral , Open Reading Frames , Phylogeny , Plant Diseases , Fusarium/virology , Plant Diseases/microbiology , Plant Diseases/virology , Fungal Viruses/genetics , Fungal Viruses/isolation & purification , Fungal Viruses/classification , RNA Viruses/genetics , RNA Viruses/isolation & purification , RNA Viruses/classification , Whole Genome Sequencing , RNA, Viral/genetics , RNA-Dependent RNA Polymerase/genetics , Viral Proteins/genetics , Cucumis melo/virology , Cucumis melo/microbiology , Amino Acid Sequence , 5' Untranslated Regions , 3' Untranslated Regions , Base Sequence
20.
Vet Rec ; 194(10): e4150, 2024 May 18.
Article in English | MEDLINE | ID: mdl-38693629

ABSTRACT

BACKGROUND: Bovine viral diarrhoea (BVD) is caused by Pestivirus A and Pestivirus B. Northern Ireland (NI) embarked on a compulsory BVD eradication scheme in 2016, which continues to this day, so an understanding of the composition of the pestivirus genotypes in the cattle population of NI is required. METHODS: This molecular epidemiology study employed 5' untranslated region (5'UTR) genetic sequencing to examine the pestivirus genotypes circulating in samples taken from a hotspot of BVD outbreaks in the Enniskillen area in 2019. RESULTS: Bovine viral diarrhoea virus (BVDV)-1e (Pestivirus A) was detected for the first time in Northern Ireland, and at a high frequency, in an infection hotspot in Enniskillen in 2019. There was no evidence of infection with BVDV-2 (Pestivirus B), Border disease virus (pestivirus D) or HoBi-like virus/BVDV-3 (pestivirus H). LIMITATIONS: Only 5'UTR sequencing was used, so supplementary sequencing, along with phylogenetic trees that include all BVDV-1 genotype reference strains, would improve accuracy. Examination of farm locations and animal movement/trade is also required. CONCLUSIONS: Genotype BVDV-1e was found for the first time in Northern Ireland, indicating an increase in the genetic diversity of BVDV-1, which could have implications for vaccine design and highlights the need for continued pestivirus genotypic surveillance.


Subject(s)
Bovine Virus Diarrhea-Mucosal Disease , Diarrhea Virus 1, Bovine Viral , Genotype , Animals , Northern Ireland/epidemiology , Cattle , Bovine Virus Diarrhea-Mucosal Disease/epidemiology , Bovine Virus Diarrhea-Mucosal Disease/virology , Diarrhea Virus 1, Bovine Viral/genetics , Diarrhea Virus 1, Bovine Viral/isolation & purification , 5' Untranslated Regions , Phylogeny , Molecular Epidemiology , Disease Outbreaks/veterinary
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