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1.
RNA regulons are essential in intestinal homeostasis.
Parham, LR, Williams, PA, Chatterji, P, Whelan, KA, Hamilton, KE
American journal of physiology. Gastrointestinal and liver physiology. 2019;(1):G197-G204
Abstract
Intestinal epithelial cells are among the most rapidly proliferating cell types in the human body. There are several different subtypes of epithelial cells, each with unique functional roles in responding to the ever-changing environment. The epithelium's ability for rapid and customized responses to environmental changes requires multitiered levels of gene regulation. An emerging paradigm in gastrointestinal epithelial cells is the regulation of functionally related mRNA families, or regulons, via RNA-binding proteins (RBPs). RBPs represent a rapid and efficient mechanism to regulate gene expression and cell function. In this review, we will provide an overview of intestinal epithelial RBPs and how they contribute specifically to intestinal epithelial stem cell dynamics. In addition, we will highlight key gaps in knowledge in the global understanding of RBPs in gastrointestinal physiology as an opportunity for future studies.
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2.
Gene-function studies in systemic lupus erythematosus.
Rosetti, F, de la Cruz, A, Crispín, JC
Current opinion in rheumatology. 2019;(2):185-192
Abstract
PURPOSE OF REVIEW The aim of this review is to discuss recent developments in our understanding of how systemic lupus erythematosus (SLE)-associated genes contribute to autoimmunity. RECENT FINDINGS Gene-function studies have revealed mechanisms through which SLE-associated alleles of IFIH1, TNFAIP3, IRF5, and PRDM1 likely contribute to the development of autoimmunity. Novel research has identified Mac-1 (encoded by ITGAM), CaMK4, and iRhom2 as plausible therapeutic targets in lupus nephritis. SUMMARY The work discussed in this review has broad implications for our understanding of the pathogenesis of SLE and for the development of novel therapeutic strategies.
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3.
Classification of the nucleolytic ribozymes based upon catalytic mechanism.
Lilley, DMJ
F1000Research. 2019
Abstract
The nucleolytic ribozymes carry out site-specific RNA cleavage reactions by nucleophilic attack of the 2'-oxygen atom on the adjacent phosphorus with an acceleration of a million-fold or greater. A major part of this arises from concerted general acid-base catalysis. Recent identification of new ribozymes has expanded the group to a total of nine and this provides a new opportunity to identify sub-groupings according to the nature of the general base and acid. These include nucleobases, hydrated metal ions, and 2'-hydroxyl groups. Evolution has selected a number of different combinations of these elements that lead to efficient catalysis. These differences provide a new mechanistic basis for classifying these ribozymes.
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Advances in CRISPR-Cas systems for RNA targeting, tracking and editing.
Wang, F, Wang, L, Zou, X, Duan, S, Li, Z, Deng, Z, Luo, J, Lee, SY, Chen, S
Biotechnology advances. 2019;(5):708-729
Abstract
Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) systems, especially type II (Cas9) systems, have been widely used in gene/genome targeting. Modifications of Cas9 enable these systems to become platforms for precise DNA manipulations. However, the utilization of CRISPR-Cas systems in RNA targeting remains preliminary. The discovery of type VI CRISPR-Cas systems (Cas13) shed light on RNA-guided RNA targeting. Cas13d, the smallest Cas13 protein, with a length of only ~930 amino acids, is a promising platform for RNA targeting compatible with viral delivery systems. Much effort has also been made to develop Cas9, Cas13a and Cas13b applications for RNA-guided RNA targeting. The discovery of new RNA-targeting CRISPR-Cas systems as well as the development of RNA-targeting platforms with Cas9 and Cas13 will promote RNA-targeting technology substantially. Here, we review new advances in RNA-targeting CRISPR-Cas systems as well as advances in applications of these systems in RNA targeting, tracking and editing. We also compare these Cas protein-based technologies with traditional technologies for RNA targeting, tracking and editing. Finally, we discuss remaining questions and prospects for the future.
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5.
Droplet-based single cell RNAseq tools: a practical guide.
Salomon, R, Kaczorowski, D, Valdes-Mora, F, Nordon, RE, Neild, A, Farbehi, N, Bartonicek, N, Gallego-Ortega, D
Lab on a chip. 2019;(10):1706-1727
Abstract
Droplet based scRNA-seq systems such as Drop-seq, inDrop and Chromium 10X have been the catalyst for the wide adoption of high-throughput scRNA-seq technologies in the research laboratory. In order to understand the capabilities of these systems to deeply interrogate biology; here we provide a practical guide through all the steps involved in a typical scRNA-seq experiment. Through comparing and contrasting these three main droplet based systems (and their derivatives), we provide an overview of all critical considerations in obtaining high quality and biologically relevant data. We also discuss the limitations of these systems and how they fit into the emerging field of Genomic Cytometry.
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6.
Metabolic Regulation of the Epitranscriptome.
Thomas, JM, Batista, PJ, Meier, JL
ACS chemical biology. 2019;(3):316-324
Abstract
An emergent theme in cancer biology is that dysregulated energy metabolism may directly influence oncogenic gene expression. This is due to the fact that many enzymes involved in gene regulation use cofactors derived from primary metabolism, including acetyl-CoA, S-adenosylmethionine, and 2-ketoglutarate. While this phenomenon was first studied through the prism of histone and DNA modifications (the epigenome), recent work indicates metabolism can also impact gene regulation by disrupting the balance of RNA post-transcriptional modifications (the epitranscriptome). Here we review recent studies that explore how metabolic regulation of writers and erasers of the epitranscriptome (FTO, TET2, NAT10, MTO1, and METTL16) helps shape gene expression through three distinct mechanisms: cofactor inhibition, cofactor depletion, and writer localization. Our brief survey underscores similarities and differences between the metabolic regulation of the epigenome and epitranscriptome, and highlights fertile ground for future investigation.
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An evolving tale of two interacting RNAs-themes and variations of the T-box riboswitch mechanism.
Suddala, KC, Zhang, J
IUBMB life. 2019;(8):1167-1180
Abstract
T-box riboswitches are a widespread class of structured noncoding RNAs in Gram-positive bacteria that regulate the expression of amino acid-related genes. They form negative feedback loops to maintain steady supplies of aminoacyl-transfer RNAs (tRNAs) to the translating ribosomes. T-box riboswitches are located in the 5' leader regions of mRNAs that they regulate and directly bind to their cognate tRNA ligands. T-boxes further sense the aminoacylation state of the bound tRNAs and, based on this readout, regulate gene expression at the level of transcription or translation. T-box riboswitches consist of two conserved domains-a 5' Stem I domain that is involved in specific tRNA recognition and a 3' antiterminator/antisequestrator (or discriminator) domain that senses the amino acid on the 3' end of the bound tRNA. Interaction of the 3' end of an uncharged but not charged tRNA with a thermodynamically weak discriminator domain stabilizes it to promote transcription readthrough or translation initiation. Recent biochemical, biophysical, and structural studies have provided high-resolution insights into the mechanism of tRNA recognition by Stem I, several structural models of full-length T-box-tRNA complexes, mechanism of amino acid sensing by the antiterminator domain, as well as kinetic details of tRNA binding to the T-box riboswitches. In addition, translation-regulating T-box riboswitches have been recently characterized, which presented key differences from the canonical transcriptional T-boxes. Here, we review the recent developments in understanding the T-box riboswitch mechanism that have employed various complementary approaches. Further, the regulation of multiple essential genes by T-boxes makes them very attractive drug targets to combat drug resistance. The recent progress in understanding the biochemical, structural, and dynamic aspects of the T-box riboswitch mechanism will enable more precise and effective targeting with small molecules. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1167-1180, 2019.
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8.
The past and presence of gene targeting: from chemicals and DNA via proteins to RNA.
Geel, TM, Ruiters, MHJ, Cool, RH, Halby, L, Voshart, DC, Andrade Ruiz, L, Niezen-Koning, KE, Arimondo, PB, Rots, MG
Philosophical transactions of the Royal Society of London. Series B, Biological sciences. 2018;(1748)
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Abstract
The ability to target DNA specifically at any given position within the genome allows many intriguing possibilities and has inspired scientists for decades. Early gene-targeting efforts exploited chemicals or DNA oligonucleotides to interfere with the DNA at a given location in order to inactivate a gene or to correct mutations. We here describe an example towards correcting a genetic mutation underlying Pompe's disease using a nucleotide-fused nuclease (TFO-MunI). In addition to the promise of gene correction, scientists soon realized that genes could be inactivated or even re-activated without inducing potentially harmful DNA damage by targeting transcriptional modulators to a particular gene. However, it proved difficult to fuse protein effector domains to the first generation of programmable DNA-binding agents. The engineering of gene-targeting proteins (zinc finger proteins (ZFPs), transcription activator-like effectors (TALEs)) circumvented this problem. The disadvantage of protein-based gene targeting is that a fusion protein needs to be engineered for every locus. The recent introduction of CRISPR/Cas offers a flexible approach to target a (fusion) protein to the locus of interest using cheap designer RNA molecules. Many research groups now exploit this platform and the first human clinical trials have been initiated: CRISPR/Cas has kicked off a new era of gene targeting and is revolutionizing biomedical sciences.This article is part of a discussion meeting issue 'Frontiers in epigenetic chemical biology'.
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9.
Circular and long non-coding RNAs and their role in ophthalmologic diseases.
Wawrzyniak, O, Zarębska, Ż, Rolle, K, Gotz-Więckowska, A
Acta biochimica Polonica. 2018;(4):497-508
Abstract
Long non-coding RNAs are 200 nucleotide long RNA molecules which lack or have limited protein-coding potential. They can regulate protein formation through several different mechanisms. Similarly, circular RNAs are reported to play a critical role in post-transcriptional gene regulation. Changes in the expression pattern of these molecules are established to underline various diseases, including cancer, cardiovascular, neurological and immunological disorders. Recent studies suggest that they are differentially expressed both in healthy ocular tissues as well as in eye pathologies, such as neovascularization, proliferative vitreoretinopathy, glaucoma, cataract, ocular malignancy or even strabismus. Aetiology of ocular diseases is multifactorial and combines genetic and environmental factors, including epigenetic and non-coding RNAs. In addition, disorders like diabetic retinopathy or age-related macular degeneration lack biomarkers for early detection as well as effective treatment methods that will allow controlling the disease progression at its early stages. The newly discovered non-coding RNAs seem to be the ideal candidate for novel molecular markers and therapeutic strategies. In this review, we summarize current knowledge about gene expression regulators - long non-coding and circular RNA molecules in eye diseases.
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RNA-targeted therapeutics for lipid disorders.
Tsimikas, S
Current opinion in lipidology. 2018;(6):459-466
Abstract
PURPOSE OF REVIEW To summarize recent developments in the field of RNA-directed therapeutics targeting lipid disorders that are not effectively managed. RECENT FINDINGS Despite a number of approved therapies for lipid disorders, significant unmet needs are present in treating persistently elevated LDL-cholesterol, remnant-cholesterol, triglycerides and lipoprotein(a) [Lp(a)]. Small molecules and antibodies are effective modalities, but they are unable to adequately treat many patients with abnormal lipid parameters. Targeting mRNA with oligonucleotides to prevent protein translation is a relatively novel method to reduce circulating atherogenic lipoproteins. Small inhibiting RNA (siRNA) molecules targeting proprotein convertase subtilisin kexin type 9 to reduce LDL-C, and antisense oligonucleotides (ASO) targeting apolipoprotein C-III (apoC-III) to reduce triglycerides, angiopoietin-like 3 (ANGPTL3) to reduce LDL-C and triglycerides and apolipoprotein(a) (LPA) to reduce Lp(a) are currently in or just completed phase 1-3 trials. Fundamental differences exist in chemistry, delivery and mechanism of action of siRNA and ASOs. SUMMARY Novel RNA therapeutics are poised to provide highly potent, specific and effective therapies to reduce atherogenic lipoproteins. As these compounds are approved, clinicians will be able to choose from a broad armamentarium to treat nearly all patients to acceptable goals in order to reduce risk of cardiovascular disease and events.