ABSTRACT
A bacterial noncoding RNA motif almost exclusively associated with pnuC genes was uncovered using comparative sequence analysis. Some PnuC proteins are known to transport nicotinamide riboside (NR), which is a component of the ubiquitous and abundant enzyme cofactor nicotinamide adenine dinucleotide (NAD+). Thus, we speculated that the newly found "pnuC motif" RNAs might function as aptamers for a novel class of NAD+-sensing riboswitches. RNA constructs that encompass the conserved nucleotides and secondary structure features that define the motif indeed selectively bind NAD+, nicotinamide mononucleotide (NMN), and NR. Mutations that disrupt strictly conserved nucleotides of the aptamer also disrupt ligand binding. These bioinformatic and biochemical findings indicate that pnuC motif RNAs are likely members of a second riboswitch class that regulates gene expression in response to NAD+ binding.
Subject(s)
Bacterial Proteins/genetics , Carrier Proteins/genetics , Coenzymes/chemistry , NAD/chemistry , Niacinamide/analogs & derivatives , Pyridinium Compounds/chemistry , Riboswitch , Streptococcus/genetics , Bacterial Proteins/metabolism , Base Sequence , Binding Sites , Carrier Proteins/metabolism , Coenzymes/metabolism , Computational Biology/methods , Corynebacterium glutamicum/genetics , Corynebacterium glutamicum/metabolism , Haemophilus influenzae/genetics , Haemophilus influenzae/metabolism , Lactobacillus acidophilus/genetics , Lactobacillus acidophilus/metabolism , NAD/metabolism , Niacinamide/chemistry , Niacinamide/metabolism , Nucleic Acid Conformation , Protein Binding , Pyridinium Compounds/metabolism , Shewanella/genetics , Shewanella/metabolism , Streptococcus/metabolismABSTRACT
Noncoding RNAs (ncRNAs) longer than 200 nucleotides are rare in bacteria, likely because bacterial genomes are under strong evolutionary pressures to maintain a small genome size. Of the long ncRNAs unique to bacteria, the OLE (ornate, large, extremophilic) RNA class is among the largest and most structurally complex. OLE RNAs form a ribonucleoprotein (RNP) complex by partnering with at least two proteins, OapA and OapB, that directly bind OLE RNA. The biochemical functions of the OLE RNP complex remain unknown, but are required for proper adaptation to certain environmental stresses, such as cold temperatures, short chain alcohols, and high magnesium concentrations. In the current study, we used electrophoretic mobility shift assays to examine the binding of OLE RNA fragments by OapB and found that OapB recognizes a small subregion of OLE RNA, including stem P13, with a dissociation constant (KD ) of â¼700 pm Analyses with mutated RNA constructs, and the application of in vitro selection, revealed that strong binding of OLE RNA by OapB requires a stem containing a precisely located single-nucleotide bulge and a GNRA tetraloop. Although the vast majority of bacteria with the ole gene also have the oapB gene, there are many whose genomes contain oapB but lack ole, suggesting that OapB has other RNA partners in some species that might exhibit similar structural features.
Subject(s)
Bacillus/chemistry , Bacterial Proteins/chemistry , RNA, Bacterial/chemistry , RNA, Untranslated/chemistry , RNA-Binding Proteins/chemistry , Bacillus/genetics , Bacillus/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , RNA, Bacterial/genetics , RNA, Bacterial/metabolism , RNA, Untranslated/genetics , RNA, Untranslated/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolismABSTRACT
3' untranslated region (3' UTR) somatic mutations represent a largely unexplored avenue of alternative oncogenic gene dysregulation. To determine the significance of 3' UTR mutations in disease, we identify 3' UTR somatic variants across 185 advanced prostate tumors, discovering 14,497 single-nucleotide mutations enriched in oncogenic pathways and 3' UTR regulatory elements. By developing two complementary massively parallel reporter assays, we measure how thousands of patient-based mutations affect mRNA translation and stability and identify hundreds of functional variants that allow us to define determinants of mutation significance. We demonstrate the clinical relevance of these mutations, observing that CRISPR-Cas9 endogenous editing of distinct variants increases cellular stress resistance and that patients harboring oncogenic 3' UTR mutations have a particularly poor prognosis. This work represents an expansive view of the extent to which disease-relevant 3' UTR mutations affect mRNA stability, translation, and cancer progression, uncovering principles of regulatory functionality and potential therapeutic targets in previously unexplored regulatory regions.
Subject(s)
Genomics , Regulatory Sequences, Nucleic Acid , Humans , 3' Untranslated Regions/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Mutation/genetics , 5' Untranslated RegionsABSTRACT
The functional consequences of genetic variants within 5' untranslated regions (UTRs) on a genome-wide scale are poorly understood in disease. Here we develop a high-throughput multi-layer functional genomics method called PLUMAGE (Pooled full-length UTR Multiplex Assay on Gene Expression) to quantify the molecular consequences of somatic 5' UTR mutations in human prostate cancer. We show that 5' UTR mutations can control transcript levels and mRNA translation rates through the creation of DNA binding elements or RNA-based cis-regulatory motifs. We discover that point mutations can simultaneously impact transcript and translation levels of the same gene. We provide evidence that functional 5' UTR mutations in the MAP kinase signaling pathway can upregulate pathway-specific gene expression and are associated with clinical outcomes. Our study reveals the diverse mechanisms by which the mutational landscape of 5' UTRs can co-opt gene expression and demonstrates that single nucleotide alterations within 5' UTRs are functional in cancer.
Subject(s)
5' Untranslated Regions/genetics , DNA Mutational Analysis/methods , Gene Expression Regulation, Neoplastic , Genomics/methods , Prostatic Neoplasms/genetics , Cell Line, Tumor , HEK293 Cells , High-Throughput Screening Assays , Humans , Male , Point Mutation , Prostate/pathology , Prostatic Neoplasms/pathology , Protein Biosynthesis/genetics , RNA-SeqABSTRACT
BACKGROUND AND AIMS: ß-Caryophyllene (BCP) is a plant-derived FDA approved food additive with anti-inflammatory properties. Some of its beneficial effects in vivo are reported to involve activation of cannabinoid CB2 receptors that are predominantly expressed in immune cells. Here, we evaluated the translational potential of BCP using a well-established model of chronic and binge alcohol-induced liver injury. METHODS: In this study, we investigated the effects of BCP on liver injury induced by chronic plus binge alcohol feeding in mice in vivo by using biochemical assays, real-time PCR and histology analyses. Serum and hepatic BCP levels were also determined by GC/MS. RESULTS: Chronic treatment with BCP alleviated the chronic and binge alcohol-induced liver injury and inflammation by attenuating the pro-inflammatory phenotypic `M1` switch of Kupffer cells and by decreasing the expression of vascular adhesion molecules intercellular adhesion molecule 1, E-Selectin and P-Selectin, as well as the neutrophil infiltration. It also beneficially influenced hepatic metabolic dysregulation (steatosis, protein hyperacetylation and PPAR-α signalling). These protective effects of BCP against alcohol-induced liver injury were attenuated in CB2 receptor knockout mice, indicating that the beneficial effects of this natural product in liver injury involve activation of these receptors. Following acute or chronic administration, BCP was detectable both in the serum and liver tissue homogenates but not in the brain. CONCLUSIONS: Given the safety of BCP in humans, this food additive has a high translational potential in treating or preventing hepatic injury associated with oxidative stress, inflammation and steatosis. LINKED ARTICLES: This article is part of a themed section on Inventing New Therapies Without Reinventing the Wheel: The Power of Drug Repurposing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.2/issuetoc.