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Khan D, Ramachandiran I, Vasu K, China A, Khan K, Cumbo F, Halawani D, Terenzi F, Zin I, Long B, Costain G, Blaser S, Carnevale A, Gogonea V, Dutta R, Blankenberg D, Yoon G, Fox PL. Homozygous EPRS1 missense variant causing hypomyelinating leukodystrophy-15 alters variant-distal mRNA m 6A site accessibility. Nat Commun 2024; 15:4284. [PMID: 38769304 PMCID: PMC11106242 DOI: 10.1038/s41467-024-48549-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 05/03/2024] [Indexed: 05/22/2024] Open
Abstract
Hypomyelinating leukodystrophy (HLD) is an autosomal recessive disorder characterized by defective central nervous system myelination. Exome sequencing of two siblings with severe cognitive and motor impairment and progressive hypomyelination characteristic of HLD revealed homozygosity for a missense single-nucleotide variant (SNV) in EPRS1 (c.4444 C > A; p.Pro1482Thr), encoding glutamyl-prolyl-tRNA synthetase, consistent with HLD15. Patient lymphoblastoid cell lines express markedly reduced EPRS1 protein due to dual defects in nuclear export and cytoplasmic translation of variant EPRS1 mRNA. Variant mRNA exhibits reduced METTL3 methyltransferase-mediated writing of N6-methyladenosine (m6A) and reduced reading by YTHDC1 and YTHDF1/3 required for efficient mRNA nuclear export and translation, respectively. In contrast to current models, the variant does not alter the sequence of m6A target sites, but instead reduces their accessibility for modification. The defect was rescued by antisense morpholinos predicted to expose m6A sites on target EPRS1 mRNA, or by m6A modification of the mRNA by METTL3-dCas13b, a targeted RNA methylation editor. Our bioinformatic analysis predicts widespread occurrence of SNVs associated with human health and disease that similarly alter accessibility of distal mRNA m6A sites. These results reveal a new RNA-dependent etiologic mechanism by which SNVs can influence gene expression and disease, consequently generating opportunities for personalized, RNA-based therapeutics targeting these disorders.
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Affiliation(s)
- Debjit Khan
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Iyappan Ramachandiran
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Kommireddy Vasu
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Arnab China
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Fabio Cumbo
- Genomic Medicine Institute, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Dalia Halawani
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Fulvia Terenzi
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Isaac Zin
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
- Department of Chemistry, Cleveland State University, Cleveland, OH, USA
| | - Briana Long
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Gregory Costain
- Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Susan Blaser
- Department of Diagnostic Imaging, Division of Neuroradiology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Amanda Carnevale
- Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, OH, USA
| | - Ranjan Dutta
- Department of Neuroscience, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Daniel Blankenberg
- Genomic Medicine Institute, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Grace Yoon
- Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Department of Paediatrics, Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA.
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Khan D, Fox PL. Host-like RNA Elements Regulate Virus Translation. Viruses 2024; 16:468. [PMID: 38543832 PMCID: PMC10976276 DOI: 10.3390/v16030468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/14/2024] [Accepted: 03/17/2024] [Indexed: 04/01/2024] Open
Abstract
Viruses are obligate, intracellular parasites that co-opt host cell machineries for propagation. Critical among these machineries are those that translate RNA into protein and their mechanisms of control. Most regulatory mechanisms effectuate their activity by targeting sequence or structural features at the RNA termini, i.e., at the 5' or 3' ends, including the untranslated regions (UTRs). Translation of most eukaryotic mRNAs is initiated by 5' cap-dependent scanning. In contrast, many viruses initiate translation at internal RNA regions at internal ribosome entry sites (IRESs). Eukaryotic mRNAs often contain upstream open reading frames (uORFs) that permit condition-dependent control of downstream major ORFs. To offset genome compression and increase coding capacity, some viruses take advantage of out-of-frame overlapping uORFs (oORFs). Lacking the essential machinery of protein synthesis, for example, ribosomes and other translation factors, all viruses utilize the host apparatus to generate virus protein. In addition, some viruses exhibit RNA elements that bind host regulatory factors that are not essential components of the translation machinery. SARS-CoV-2 is a paradigm example of a virus taking advantage of multiple features of eukaryotic host translation control: the virus mimics the established human GAIT regulatory element and co-opts four host aminoacyl tRNA synthetases to form a stimulatory binding complex. Utilizing discontinuous transcription, the elements are present and identical in all SARS-CoV-2 subgenomic RNAs (and the genomic RNA). Thus, the virus exhibits a post-transcriptional regulon that improves upon analogous eukaryotic regulons, in which a family of functionally related mRNA targets contain elements that are structurally similar but lacking sequence identity. This "thrifty" virus strategy can be exploited against the virus since targeting the element can suppress the expression of all subgenomic RNAs as well as the genomic RNA. Other 3' end viral elements include 3'-cap-independent translation elements (3'-CITEs) and 3'-tRNA-like structures. Elucidation of virus translation control elements, their binding proteins, and their mechanisms can lead to novel therapeutic approaches to reduce virus replication and pathogenicity.
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Affiliation(s)
- Debjit Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Paul L. Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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Kouprina N, Larionov V. Transformation-associated recombination (TAR) cloning and its applications for gene function; genome architecture and evolution; biotechnology and biomedicine. Oncotarget 2023; 14:1009-1033. [PMID: 38147065 PMCID: PMC10750837 DOI: 10.18632/oncotarget.28546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 11/27/2023] [Indexed: 12/27/2023] Open
Abstract
Transformation-associated recombination (TAR) cloning represents a unique tool to selectively and efficiently recover a given chromosomal segment up to several hundred kb in length from complex genomes (such as animals and plants) and simple genomes (such as bacteria and viruses). The technique exploits a high level of homologous recombination in the yeast Sacharomyces cerevisiae. In this review, we summarize multiple applications of the pioneering TAR cloning technique, developed previously for complex genomes, for functional, evolutionary, and structural studies, and extended the modified TAR versions to isolate biosynthetic gene clusters (BGCs) from microbes, which are the major source of pharmacological agents and industrial compounds, and to engineer synthetic viruses with novel properties to design a new generation of vaccines. TAR cloning was adapted as a reliable method for the assembly of synthetic microbe genomes for fundamental research. In this review, we also discuss how the TAR cloning in combination with HAC (human artificial chromosome)- and CRISPR-based technologies may contribute to the future.
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Affiliation(s)
- Natalay Kouprina
- Developmental Therapeutics Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Vladimir Larionov
- Developmental Therapeutics Branch, National Cancer Institute, Bethesda, MD 20892, USA
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Khan D, Fox PL. Aminoacyl-tRNA synthetase interactions in SARS-CoV-2 infection. Biochem Soc Trans 2023; 51:2127-2141. [PMID: 38108455 PMCID: PMC10754286 DOI: 10.1042/bst20230527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are ancient enzymes that serve a foundational role in the efficient and accurate translation of genetic information from messenger RNA to proteins. These proteins play critical, non-canonical functions in a multitude of cellular processes. Multiple viruses are known to hijack the functions of aaRSs for proviral outcomes, while cells modify antiviral responses through non-canonical functions of certain synthetases. Recent findings have revealed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of coronaviral disease 19 (COVID-19), utilizes canonical and non-canonical functions of aaRSs, establishing a complex interplay of viral proteins, cellular factors and host aaRSs. In a striking example, an unconventional multi-aaRS complex consisting of glutamyl-prolyl-, lysyl-, arginyl- and methionyl-tRNA synthetases interact with a previously unknown RNA-element in the 3'-end of SARS-CoV-2 genomic and subgenomic RNAs. This review aims to highlight the aaRS-SARS-CoV-2 interactions identified to date, with possible implications for the biology of host aaRSs in SARS-CoV-2 infection.
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Affiliation(s)
- Debjit Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A
| | - Paul L. Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A
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