201
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de Villiers EM, Gunst K, Chakraborty D, Ernst C, Bund T, Zur Hausen H. A specific class of infectious agents isolated from bovine serum and dairy products and peritumoral colon cancer tissue. Emerg Microbes Infect 2019; 8:1205-1218. [PMID: 31409221 PMCID: PMC6713099 DOI: 10.1080/22221751.2019.1651620] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The in silico analyses of 109 replication-competent genomic DNA sequences isolated from cow milk and its products (97 in the bovine meat and milk factors 2 group – BMMF2, and additional 4 in BMMF1) seems to place these in a specific class of infectious agents spanning between bacterial plasmid and circular ssDNA viruses. Satellite-type small plasmids with partial homology to larger genomes, were also isolated in both groups. A member of the BMMF1 group H1MBS.1 was recovered in a distinctly modified form from colon tissue by laser microdissection. Although the evolutionary origin is unknown, it draws the attention to the existence of a hitherto unrecognized, broad spectrum of potential pathogens. Indirect hints to the origin and structure of our isolates, as well as to their replicative behaviour, result from parallels drawn to the Hepatitis deltavirus genome structure and replication.
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Affiliation(s)
- Ethel-Michele de Villiers
- a Episomal-Persistent DNA in Cancer- and Chronic Diseases, Deutsches Krebsforschungszentrum , Heidelberg , Germany
| | - Karin Gunst
- a Episomal-Persistent DNA in Cancer- and Chronic Diseases, Deutsches Krebsforschungszentrum , Heidelberg , Germany
| | - Deblina Chakraborty
- a Episomal-Persistent DNA in Cancer- and Chronic Diseases, Deutsches Krebsforschungszentrum , Heidelberg , Germany
| | - Claudia Ernst
- a Episomal-Persistent DNA in Cancer- and Chronic Diseases, Deutsches Krebsforschungszentrum , Heidelberg , Germany
| | - Timo Bund
- a Episomal-Persistent DNA in Cancer- and Chronic Diseases, Deutsches Krebsforschungszentrum , Heidelberg , Germany
| | - Harald Zur Hausen
- a Episomal-Persistent DNA in Cancer- and Chronic Diseases, Deutsches Krebsforschungszentrum , Heidelberg , Germany
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202
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Manjunath H, Zhang H, Rehfeld F, Han J, Chang TC, Mendell JT. Suppression of Ribosomal Pausing by eIF5A Is Necessary to Maintain the Fidelity of Start Codon Selection. Cell Rep 2019; 29:3134-3146.e6. [PMID: 31801078 PMCID: PMC6917043 DOI: 10.1016/j.celrep.2019.10.129] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022] Open
Abstract
Sequences within 5' UTRs dictate the site and efficiency of translation initiation. In this study, an unbiased screen designed to interrogate the 5' UTR-mediated regulation of the growth-promoting gene MYC unexpectedly revealed the ribosomal pause relief factor eIF5A as a regulator of translation initiation codon selection. Depletion of eIF5A enhances upstream translation within 5' UTRs across yeast and human transcriptomes, including on the MYC transcript, where this results in increased production of an N-terminally extended protein. Furthermore, ribosome profiling experiments established that the function of eIF5A as a suppressor of ribosomal pausing at sites of suboptimal peptide bond formation is conserved in human cells. We present evidence that proximal ribosomal pausing on a transcript triggers enhanced use of upstream suboptimal or non-canonical initiation codons. Thus, we propose that eIF5A functions not only to maintain efficient translation elongation in eukaryotic cells but also to maintain the fidelity of translation initiation.
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Affiliation(s)
- Hema Manjunath
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - He Zhang
- Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA; Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA
| | - Frederick Rehfeld
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Jaeil Han
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Joshua T Mendell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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203
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Monteuuis G, Miścicka A, Świrski M, Zenad L, Niemitalo O, Wrobel L, Alam J, Chacinska A, Kastaniotis AJ, Kufel J. Non-canonical translation initiation in yeast generates a cryptic pool of mitochondrial proteins. Nucleic Acids Res 2019; 47:5777-5791. [PMID: 31216041 PMCID: PMC6582344 DOI: 10.1093/nar/gkz301] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/12/2019] [Accepted: 04/16/2019] [Indexed: 12/15/2022] Open
Abstract
Utilization of non-AUG alternative translation start sites is most common in bacteria and viruses, but it has been also reported in other organisms. This phenomenon increases proteome complexity by allowing expression of multiple protein isoforms from a single gene. In Saccharomyces cerevisiae, a few described cases concern proteins that are translated from upstream near-cognate start codons as N-terminally extended variants that localize to mitochondria. Using bioinformatics tools, we provide compelling evidence that in yeast the potential for producing alternative protein isoforms by non-AUG translation initiation is much more prevalent than previously anticipated and may apply to as many as a few thousand proteins. Several hundreds of candidates are predicted to gain a mitochondrial targeting signal (MTS), generating an unrecognized pool of mitochondrial proteins. We confirmed mitochondrial localization of a subset of proteins previously not identified as mitochondrial, whose standard forms do not carry an MTS. Our data highlight the potential of non-canonical translation initiation in expanding the capacity of the mitochondrial proteome and possibly also other cellular features.
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Affiliation(s)
- Geoffray Monteuuis
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Anna Miścicka
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Lounis Zenad
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Olli Niemitalo
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Lidia Wrobel
- International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Jahangir Alam
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Agnieszka Chacinska
- International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.,Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Alexander J Kastaniotis
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FIN-90014 Finland
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
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204
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Landrau-Giovannetti N, Subramaniam K, Brown MA, Ng TFF, Rotstein DS, West K, Frasca S, Waltzek TB. Genomic characterization of a novel circovirus from a stranded Longman's beaked whale (Indopacetus pacificus). Virus Res 2019; 277:197826. [PMID: 31790774 DOI: 10.1016/j.virusres.2019.197826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 11/28/2022]
Abstract
Tissues from a juvenile Longman's beaked whale that stranded in Hawaii in 2010 were screened for viruses using a Next-Generation Sequencing (NGS) approach. From the NGS data, the full genome (1,849 bp) of a novel beaked whale circovirus (BWCV) was determined. Two open reading frames (ORF) were annotated, including ORF1 that encodes the capsid gene, ORF2 that encodes the replication-associated gene, and a 9-bp conserved nonamer on the apex of the open loop found in all circoviruses. Independent phylogenetic analyses based on amino acid sequence alignments of the two CV proteins supported the BWCV as a member of the genus Circovirus, branching as the sister species to the recently discovered canine circovirus. A sequence identity matrix generated from complete genome alignments revealed the BWCV displays between from 51.1 to 56.7% nucleotide identity to other circoviruses, which is lower than the 80% threshold proposed for species demarcation. Considering the genetic and phylogenetic analyses, we propose the formal species designation of beaked whale circovirus. An endpoint PCR assay targeting the BWCV genome confirmed the presence of the BWCV DNA in every tissue from which DNA was extracted, including spleen, muscle, left ventricle, left adrenal gland, liver, lung, cerebrum, cerebellum, and lymph node. An automated in situ hybridization assay utilizing RNAscope® technology and targeting the replication-associated gene resulted in labeling of individual cells morphologically resembling mononuclear leukocytes and cells of blood vessels in diaphragm, liver, lymph nodes, lung, pericardium, oral mucosa and tongue, adrenal gland, testis, aorta, intestine, stomach and heart. The clinical or pathologic significance of BWCV is undetermined, as are its host range, prevalence, and pathogenicity in cetaceans of Hawaiian waters and elsewhere.
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Affiliation(s)
- Nelmarie Landrau-Giovannetti
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Melissa Ann Brown
- Molecular Histotechnology Laboratory, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Terry Fei Fan Ng
- College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | | | - Kristi West
- Hawaii Institute of Marine Biology, University of Hawaii at Manoa, PO Box 1346, Kaneohe, HI, United States; Department of Human Nutrition Food and Animal Science, College of Tropical Agriculture and Human Resources, 1955 East-West Road, University of Hawaii at Manoa Ag Sci 216, Honolulu, HI 96822, United States
| | - Salvatore Frasca
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.
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205
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Herring SK, Moon HJ, Rawal P, Chhibber A, Zhao L. Brain clusterin protein isoforms and mitochondrial localization. eLife 2019; 8:48255. [PMID: 31738162 PMCID: PMC6860991 DOI: 10.7554/elife.48255] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/24/2019] [Indexed: 01/04/2023] Open
Abstract
Clusterin (CLU), or apolipoprotein J (ApoJ), is the third most predominant genetic risk factor associated with late-onset Alzheimer’s disease (LOAD). In this study, we use multiple rodent and human brain tissue and neural cell models to demonstrate that CLU is expressed as multiple isoforms that have distinct cellular or subcellular localizations in the brain. Of particular significance, we identify a non-glycosylated 45 kDa CLU isoform (mitoCLU) that is localized to the mitochondrial matrix and expressed in both rodent and human neurons and astrocytes. In addition, we show that rodent mitoCLU is translated from a non-canonical CUG (Leu) start site in Exon 3, a site that coincides with an AUG (Met) in human CLU. Last, we reveal that mitoCLU is present at the gene and protein level in the currently available CLU–/– mouse model. Collectively, these data provide foundational knowledge that is integral in elucidating the relationship between CLU and the development of LOAD.
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Affiliation(s)
- Sarah K Herring
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Hee-Jung Moon
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Punam Rawal
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Anindit Chhibber
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States
| | - Liqin Zhao
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, United States.,Neuroscience Graduate Program, University of Kansas, Lawrence, United States
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206
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Oleaga-Quintas C, Deswarte C, Moncada-Vélez M, Metin A, Krishna Rao I, Kanık-Yüksek S, Nieto-Patlán A, Guérin A, Gülhan B, Murthy S, Özkaya-Parlakay A, Abel L, Martínez-Barricarte R, Pérez de Diego R, Boisson-Dupuis S, Kong XF, Casanova JL, Bustamante J. A purely quantitative form of partial recessive IFN-γR2 deficiency caused by mutations of the initiation or second codon. Hum Mol Genet 2019; 27:3919-3935. [PMID: 31222290 DOI: 10.1093/hmg/ddy275] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/17/2018] [Accepted: 07/17/2018] [Indexed: 02/07/2023] Open
Abstract
Mendelian susceptibility to mycobacterial disease (MSMD) is characterized by clinical disease caused by weakly virulent mycobacteria, such as environmental mycobacteria and Bacillus Calmette-Guérin vaccines, in otherwise healthy individuals. All known genetic etiologies disrupt interferon (IFN)-γ immunity. Germline bi-allelic mutations of IFNGR2 can underlie partial or complete forms of IFN-γ receptor 2 (IFN-γR2) deficiency. Patients with partial IFN-γR2 deficiency express a dysfunctional molecule on the cell surface. We studied three patients with MSMD from two unrelated kindreds from Turkey (P1, P2) and India (P3), by whole-exome sequencing. P1 and P2 are homozygous for a mutation of the initiation codon(c.1A>G) of IFNGR2, whereas P3 is homozygous for a mutation of the second codon (c.4delC). Overexpressed mutant alleles produce small amounts of full-length IFN-γR2 resulting in an impaired, but not abolished, response to IFN-γ. Moreover, SV40-fibroblasts of P1 and P2 responded weakly to IFN-γ, and Epstein Barr virus-transformed B cells had a barely detectable response to IFN-γ. Studies in patients' primary T cells and monocyte-derived macrophages yielded similar results. The residual expression of IFN-γR2 protein of normal molecular weight and function is due to the initiation of translation between the second and ninth non-AUG codons. We thus describe mutations of the first and second codons of IFNGR2, which define a new form of partial recessive IFN-γR2 deficiency. Residual levels of IFN-γ signaling were very low, accounting for the more severe clinical phenotype of these patients with residual expression levels of normally functional surface receptors than of patients with partial recessive IFN-γR2 deficiency due to surface-expressed dysfunctional receptors, whose residual levels of IFN-γ signaling were higher.
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Affiliation(s)
- Carmen Oleaga-Quintas
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France.,Department of Immunology, School of Medicine, Complutense University, Madrid, Spain
| | - Caroline Deswarte
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France
| | - Marcela Moncada-Vélez
- Primary Immunodeficiencies Group, School of Medicine, University of Antioquia UdeA, Medellin, Colombia
| | - Ayse Metin
- Infectious Diseases Unit, Ankara Hematology Oncology Children's Training and Research Hospital, Ankara, Turkey
| | | | - Saliha Kanık-Yüksek
- Infectious Diseases Unit, Ankara Hematology Oncology Children's Training and Research Hospital, Ankara, Turkey
| | - Alejandro Nieto-Patlán
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France
| | - Antoine Guérin
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France
| | - Belgin Gülhan
- Infectious Diseases Unit, Ankara Hematology Oncology Children's Training and Research Hospital, Ankara, Turkey
| | - Savita Murthy
- Department of Pediatrics, St John's Medical College, Bangalore, India
| | - Aslınur Özkaya-Parlakay
- Infectious Diseases Unit, Ankara Hematology Oncology Children's Training and Research Hospital, Ankara, Turkey
| | - Laurent Abel
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France.,St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, the Rockefeller University, New York, USA
| | - Rubén Martínez-Barricarte
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, the Rockefeller University, New York, USA
| | - Rebeca Pérez de Diego
- Laboratory of Immunogenetics of Human Diseases IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Stéphanie Boisson-Dupuis
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France.,St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, the Rockefeller University, New York, USA
| | - Xiao-Fei Kong
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, the Rockefeller University, New York, USA
| | - Jean-Laurent Casanova
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France.,St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, the Rockefeller University, New York, USA.,Howard Hughes Medical Institute, New York, USA.,Pediatric Hematology-Immunology Unit, AP-HP, Necker Hospital for Sick Children, Paris, France
| | - Jacinta Bustamante
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR1163, Imagine Institute, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Paris, France.,St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, the Rockefeller University, New York, USA.,Center for the Study of Primary Immunodeficiencies, AP-HP, Necker Hospital for Sick Children, Paris, France
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207
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Choi S, Ju S, Lee J, Na S, Lee C, Paek E. Proteogenomic Approach to UTR Peptide Identification. J Proteome Res 2019; 19:212-220. [DOI: 10.1021/acs.jproteome.9b00498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
| | - Shinyeong Ju
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | | | | | - Cheolju Lee
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Republic of Korea
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208
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Abstract
PTEN is a phosphatase that functions as a tumour suppressor by antagonizing the PI3K–AKT pathway. However, a study now demonstrates that translational variants of PTEN enable new interactions between PTEN and the COMPASS complex, identifying a new role for PTEN in modifying gene expression via COMPASS-mediated histone H3 lysine 4 methylation.
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Affiliation(s)
- Justin Taylor
- Leukemia Service and Human Oncology and Pathogenesis Program, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Omar Abdel-Wahab
- Leukemia Service and Human Oncology and Pathogenesis Program, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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209
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Sun P, Li G. CircCode: A Powerful Tool for Identifying circRNA Coding Ability. Front Genet 2019; 10:981. [PMID: 31649739 PMCID: PMC6795751 DOI: 10.3389/fgene.2019.00981] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/13/2019] [Indexed: 01/25/2023] Open
Abstract
Circular RNAs (circRNAs), which play vital roles in many regulatory pathways, are widespread in many species. Although many circRNAs have been discovered in plants and animals, the functions of these RNAs have not been fully investigated. In addition to the function of circRNAs as microRNA (miRNA) decoys, the translation potential of circRNAs is important for the study of their functions; yet, few tools are available to identify their translation potential. With the development of high-throughput sequencing technology and the emergence of ribosome profiling technology, it is possible to identify the coding ability of circRNAs with high sensitivity. To evaluate the coding ability of circRNAs, we first developed the CircCode tool and then used CircCode to investigate the translation potential of circRNAs from humans and Arabidopsis thaliana. Based on the ribosome profile databases downloaded from NCBI, we found 3,610 and 1,569 translated circRNAs in humans and A. thaliana, respectively. Finally, we tested the performance of CircCode and found a low false discovery rate and high sensitivity for identifying circRNA coding ability. CircCode, a Python 3-based framework for identifying the coding ability of circRNAs, is also a simple and powerful command line-based tool. To investigate the translation potential of circRNAs, the user can simply fill in the given configuration file and run the Python 3 scripts. The tool is freely available at https://github.com/PSSUN/CircCode.
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Affiliation(s)
- Peisen Sun
- Key Laboratory of Ministry of Education for Medicinal Plant Resource and Natural Pharmaceutical Chemistry, Shaanxi Normal University, Xi’an, China
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Guanglin Li
- Key Laboratory of Ministry of Education for Medicinal Plant Resource and Natural Pharmaceutical Chemistry, Shaanxi Normal University, Xi’an, China
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
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210
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Zheng GZ, Li W, Liu ZY. Alternative role of noncoding RNAs: coding and noncoding properties. J Zhejiang Univ Sci B 2019; 20:920-927. [PMID: 31595728 DOI: 10.1631/jzus.b1900336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Noncoding RNAs (ncRNAs) have played a critical role in cellular biological functions. Recently, some peptides or proteins originating from annotated ncRNAs were identified in organism development and various diseases. Here, we briefly review several novel peptides translated by annotated ncRNAs and related key functions. In addition, we summarize the potential mechanism of bifunctional ncRNAs and propose a specific "switch" triggering the transformation from the noncoding to the coding state under certain stimuli or cellular stress. The coding properties of ncRNAs and their peptide products may provide a novel horizon in proteomic research and can be regarded as a potential therapeutic target for the treatment of various diseases.
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Affiliation(s)
- Gui-Zhen Zheng
- Department of Emergency Internal Medicine, Shanghai East Hospital, Tongji University, Shanghai 200120, China
| | - Wei Li
- Department of General Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Zhi-Yong Liu
- Department of Laboratory Diagnostics, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.,Kunming General Hospital of Chengdu Military Command, Kunming 650032, China
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211
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Mudge JM, Jungreis I, Hunt T, Gonzalez JM, Wright JC, Kay M, Davidson C, Fitzgerald S, Seal R, Tweedie S, He L, Waterhouse RM, Li Y, Bruford E, Choudhary JS, Frankish A, Kellis M. Discovery of high-confidence human protein-coding genes and exons by whole-genome PhyloCSF helps elucidate 118 GWAS loci. Genome Res 2019; 29:2073-2087. [PMID: 31537640 PMCID: PMC6886504 DOI: 10.1101/gr.246462.118] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 09/09/2019] [Indexed: 12/15/2022]
Abstract
The most widely appreciated role of DNA is to encode protein, yet the exact portion of the human genome that is translated remains to be ascertained. We previously developed PhyloCSF, a widely used tool to identify evolutionary signatures of protein-coding regions using multispecies genome alignments. Here, we present the first whole-genome PhyloCSF prediction tracks for human, mouse, chicken, fly, worm, and mosquito. We develop a workflow that uses machine learning to predict novel conserved protein-coding regions and efficiently guide their manual curation. We analyze more than 1000 high-scoring human PhyloCSF regions and confidently add 144 conserved protein-coding genes to the GENCODE gene set, as well as additional coding regions within 236 previously annotated protein-coding genes, and 169 pseudogenes, most of them disabled after primates diverged. The majority of these represent new discoveries, including 70 previously undetected protein-coding genes. The novel coding genes are additionally supported by single-nucleotide variant evidence indicative of continued purifying selection in the human lineage, coding-exon splicing evidence from new GENCODE transcripts using next-generation transcriptomic data sets, and mass spectrometry evidence of translation for several new genes. Our discoveries required simultaneous comparative annotation of other vertebrate genomes, which we show is essential to remove spurious ORFs and to distinguish coding from pseudogene regions. Our new coding regions help elucidate disease-associated regions by revealing that 118 GWAS variants previously thought to be noncoding are in fact protein altering. Altogether, our PhyloCSF data sets and algorithms will help researchers seeking to interpret these genomes, while our new annotations present exciting loci for further experimental characterization.
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Affiliation(s)
- Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Irwin Jungreis
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, Massachusetts 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Toby Hunt
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Jose Manuel Gonzalez
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - James C Wright
- Functional Proteomics, Division of Cancer Biology, Institute of Cancer Research, London SW7 3RP, United Kingdom
| | - Mike Kay
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Claire Davidson
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Stephen Fitzgerald
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Ruth Seal
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom.,Department of Haematology, University of Cambridge, Cambridge CB2 0PT, United Kingdom
| | - Susan Tweedie
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Liang He
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, Massachusetts 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Robert M Waterhouse
- Department of Ecology and Evolution, University of Lausanne, Lausanne 1015, Switzerland.,Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | - Yue Li
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, Massachusetts 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Elspeth Bruford
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom.,Department of Haematology, University of Cambridge, Cambridge CB2 0PT, United Kingdom
| | - Jyoti S Choudhary
- Functional Proteomics, Division of Cancer Biology, Institute of Cancer Research, London SW7 3RP, United Kingdom
| | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Manolis Kellis
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, Massachusetts 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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212
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Dent P, Booth L, Poklepovic A, Hancock JF. Signaling alterations caused by drugs and autophagy. Cell Signal 2019; 64:109416. [PMID: 31520735 DOI: 10.1016/j.cellsig.2019.109416] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022]
Abstract
Autophagy is an evolutionary conserved process that recycles cellular materials in times of nutrient restriction to maintain viability. In cancer therapeutics, the role of autophagy in response to multi-kinase inhibitors, alone or when combined with histone deacetylase (HDAC) inhibitors acts, generally, to facilitate the killing of tumor cells. Furthermore, the formation of autophagosomes and subsequent degradation of their contents can reduce the expression of HDAC proteins themselves as well as of other signaling regulatory molecules such as protein chaperones and mutated RAS proteins. Reduced levels of HDAC6 causes the acetylation and inactivation of heat shock protein 90, and, together with reduced expression of the chaperones HSP70 and GRP78, generates a strong endoplasmic reticulum (ER) stress response. Prolonged intense ER stress signaling causes tumor cell death. Reduced expression of HDACs 1, 2 and 3 causes the levels of programed death ligand 1 (PD-L1) to decline and the expression of Class I MHCA to increase which correlates with elevated immunogenicity of the tumor cells in vivo. This review will specifically focus on the downstream implications that result from autophagic-degradation of HDACs, RAS and protein chaperones.
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Affiliation(s)
- Paul Dent
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
| | - Laurence Booth
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Andrew Poklepovic
- Department of Biochemistry and Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA
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213
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Lacerda R, Menezes J, Candeias MM. Alternative Mechanisms of mRNA Translation Initiation in Cellular Stress Response and Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1157:117-132. [PMID: 31342440 DOI: 10.1007/978-3-030-19966-1_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Throughout evolution, eukaryotic cells have devised different mechanisms to cope with stressful environments. When eukaryotic cells are exposed to stress stimuli, they activate adaptive pathways that allow them to restore cellular homeostasis. Most types of stress stimuli have been reported to induce a decrease in overall protein synthesis accompanied by induction of alternative mechanisms of mRNA translation initiation. Here, we present well-studied and recent examples of such stress responses and the alternative translation initiation mechanisms they induce, and discuss the consequences of such regulation for cell homeostasis and oncogenic transformation.
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Affiliation(s)
- Rafaela Lacerda
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Lisboa, Portugal.,Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisbon, Lisboa, Portugal
| | - Juliane Menezes
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Lisboa, Portugal.,Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisbon, Lisboa, Portugal
| | - Marco M Candeias
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Lisboa, Portugal. .,MaRCU - Molecular and RNA Cancer Unit, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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214
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Tahmasebi S, Sonenberg N, Hershey JWB, Mathews MB. Protein Synthesis and Translational Control: A Historical Perspective. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035584. [PMID: 30082466 DOI: 10.1101/cshperspect.a035584] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein synthesis and its regulation are central to all known forms of life and impinge on biological arenas as varied as agriculture, biotechnology, and medicine. Otherwise known as translation and translational control, these processes have been investigated with increasing intensity since the middle of the 20th century, and in increasing depth with advances in molecular and cell biology. We review the origins of the field, focusing on the underlying concepts and early studies of the cellular machinery and mechanisms involved. We highlight key discoveries and events on a timeline, consider areas where current research has engendered new ideas, and conclude with some speculation on future directions for the field.
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Affiliation(s)
- Soroush Tahmasebi
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montreal, QC H3A 1A3, Canada
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montreal, QC H3A 1A3, Canada
| | - John W B Hershey
- Department of Biochemistry and Molecular Medicine, University of California, School of Medicine, Davis, California 95616
| | - Michael B Mathews
- Department of Medicine, Rutgers New Jersey Medical School, Newark, New Jersey 07103
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215
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Li F, Zhang S, Fu C, Li T, Cui X. Molecular and functional analysis of the insulin-like peptides gene in the oriental river prawn Macrobrachium nipponense. Gen Comp Endocrinol 2019; 280:209-214. [PMID: 31075271 DOI: 10.1016/j.ygcen.2019.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 04/25/2019] [Accepted: 05/06/2019] [Indexed: 02/06/2023]
Abstract
The insulin-like peptide (ILP) family is a group of evolutionarily conserved proteins that control body size and organ growth in metazoans. In the current study we describe, for the first time, the Mn-ILP gene in the oriental river prawn Macrobrachium nipponense. Full-length of the Mn-ILP cDNA was 1630 bp, encoding 174 amino acids. The deduced amino acid sequence of Mn-ILP had the typical features of ILP proteins, including two cleavage sites and six conserved cysteines. To define the function of Mn-ILP, the expression ofthe Mn-ILP gene in different growth stages of prawns of both sexes, in male prawns of different sizes, and in prawns at different stages of the molt cycle was analyzed by qRT-PCR. Mn-ILP expression was significantly higher 1) in the rapid growth stage than in the other stages of male prawns; 2) in the normal growth stage than in the gonad development stage of female prawns; 3) in big male prawns than in small male prawns; and 4) in the intermolt stage than in the other stages of the molt cycle in prawns of the same size. Further, silencing Mn-ILP expression by RNAi effectively slowed down the growth speed of M. nipponense. Thus, Mn-ILP appears to have an important role in the growth and development process of M. nipponense.
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Affiliation(s)
- Fajun Li
- Shandong Peninsula Engineering Research Center of Comprehensive Brine Utilization, Weifang University of Science and Technology, Shouguang 262700, PR China; Jiasixie Agricultural School, Weifang University of Science and Technology, Shouguang 262700, PR China.
| | - Shiyong Zhang
- Freshwater Fisheries Research Institute of Jiangsu Province, Nanjing 210017, PR China
| | - Chunpeng Fu
- Shandong Peninsula Engineering Research Center of Comprehensive Brine Utilization, Weifang University of Science and Technology, Shouguang 262700, PR China; Jiasixie Agricultural School, Weifang University of Science and Technology, Shouguang 262700, PR China
| | - Tingting Li
- Shandong Peninsula Engineering Research Center of Comprehensive Brine Utilization, Weifang University of Science and Technology, Shouguang 262700, PR China; Jiasixie Agricultural School, Weifang University of Science and Technology, Shouguang 262700, PR China
| | - Xinyu Cui
- Jiasixie Agricultural School, Weifang University of Science and Technology, Shouguang 262700, PR China
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216
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Wu HYL, Song G, Walley JW, Hsu PY. The Tomato Translational Landscape Revealed by Transcriptome Assembly and Ribosome Profiling. PLANT PHYSIOLOGY 2019; 181:367-380. [PMID: 31248964 PMCID: PMC6716236 DOI: 10.1104/pp.19.00541] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/10/2019] [Indexed: 05/14/2023]
Abstract
Recent applications of translational control in Arabidopsis (Arabidopsis thaliana) highlight the potential power of manipulating mRNA translation for crop improvement. However, to what extent translational regulation is conserved between Arabidopsis and other species is largely unknown, and the translatome of most crops remains poorly studied. Here, we combined de novo transcriptome assembly and ribosome profiling to study global mRNA translation in tomato (Solanum lycopersicum) roots. Exploiting features corresponding to active translation, we discovered widespread unannotated translation events, including 1,329 upstream open reading frames (uORFs) within the 5' untranslated regions of annotated coding genes and 354 small ORFs (sORFs) among unannotated transcripts. uORFs may repress translation of their downstream main ORFs, whereas sORFs may encode signaling peptides. Besides evolutionarily conserved sORFs, we uncovered 96 Solanaceae-specific sORFs, revealing the importance of studying translatomes directly in crops. Proteomic analysis confirmed that some of the unannotated ORFs generate stable proteins in planta. In addition to defining the translatome, our results reveal the global regulation by uORFs and microRNAs. Despite diverging over 100 million years ago, many translational features are well conserved between Arabidopsis and tomato. Thus, our approach provides a high-throughput method to discover unannotated ORFs, elucidates evolutionarily conserved and unique translational features, and identifies regulatory mechanisms hidden in a crop genome.
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Affiliation(s)
- Hsin-Yen Larry Wu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Gaoyuan Song
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011
| | - Justin W Walley
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011
| | - Polly Yingshan Hsu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
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217
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Linsalata AE, He F, Malik AM, Glineburg MR, Green KM, Natla S, Flores BN, Krans A, Archbold HC, Fedak SJ, Barmada SJ, Todd PK. DDX3X and specific initiation factors modulate FMR1 repeat-associated non-AUG-initiated translation. EMBO Rep 2019; 20:e47498. [PMID: 31347257 PMCID: PMC6726903 DOI: 10.15252/embr.201847498] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 06/19/2019] [Accepted: 06/26/2019] [Indexed: 12/12/2022] Open
Abstract
A CGG trinucleotide repeat expansion in the 5' UTR of FMR1 causes the neurodegenerative disorder Fragile X-associated tremor/ataxia syndrome (FXTAS). This repeat supports a non-canonical mode of protein synthesis known as repeat-associated, non-AUG (RAN) translation. The mechanism underlying RAN translation at CGG repeats remains unclear. To identify modifiers of RAN translation and potential therapeutic targets, we performed a candidate-based screen of eukaryotic initiation factors and RNA helicases in cell-based assays and a Drosophila melanogaster model of FXTAS. We identified multiple modifiers of toxicity and RAN translation from an expanded CGG repeat in the context of the FMR1 5'UTR. These include the DEAD-box RNA helicase belle/DDX3X, the helicase accessory factors EIF4B/4H, and the start codon selectivity factors EIF1 and EIF5. Disrupting belle/DDX3X selectively inhibited FMR1 RAN translation in Drosophila in vivo and cultured human cells, and mitigated repeat-induced toxicity in Drosophila and primary rodent neurons. These findings implicate RNA secondary structure and start codon fidelity as critical elements mediating FMR1 RAN translation and identify potential targets for treating repeat-associated neurodegeneration.
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Affiliation(s)
- Alexander E Linsalata
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Fang He
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Department of Biological and Health SciencesTexas A&M University, KingsvilleKingsvilleTXUSA
| | - Ahmed M Malik
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | | | - Katelyn M Green
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Sam Natla
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Brittany N Flores
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Amy Krans
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | | | | | - Sami J Barmada
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Peter K Todd
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Ann Arbor VA Medical CenterAnn ArborMIUSA
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218
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Hodson N, West DWD, Philp A, Burd NA, Moore DR. Molecular regulation of human skeletal muscle protein synthesis in response to exercise and nutrients: a compass for overcoming age-related anabolic resistance. Am J Physiol Cell Physiol 2019; 317:C1061-C1078. [PMID: 31461340 DOI: 10.1152/ajpcell.00209.2019] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Skeletal muscle mass, a strong predictor of longevity and health in humans, is determined by the balance of two cellular processes, muscle protein synthesis (MPS) and muscle protein breakdown. MPS seems to be particularly sensitive to changes in mechanical load and/or nutritional status; therefore, much research has focused on understanding the molecular mechanisms that underpin this cellular process. Furthermore, older individuals display an attenuated MPS response to anabolic stimuli, termed anabolic resistance, which has a negative impact on muscle mass and function, as well as quality of life. Therefore, an understanding of which, if any, molecular mechanisms contribute to anabolic resistance of MPS is of vital importance in formulation of therapeutic interventions for such populations. This review summarizes the current knowledge of the mechanisms that underpin MPS, which are broadly divided into mechanistic target of rapamycin complex 1 (mTORC1)-dependent, mTORC1-independent, and ribosomal biogenesis-related, and describes the evidence that shows how they are regulated by anabolic stimuli (exercise and/or nutrition) in healthy human skeletal muscle. This review also summarizes evidence regarding which of these mechanisms may be implicated in age-related skeletal muscle anabolic resistance and provides recommendations for future avenues of research that can expand our knowledge of this area.
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Affiliation(s)
- Nathan Hodson
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Daniel W D West
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Philp
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Nicholas A Burd
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Daniel R Moore
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
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219
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Volloch V, Rits S, Olsen BR. RNA-dependent Amplification of Mammalian mRNA Encoding Extracellullar Matrix Proteins: Identification of Chimeric RNA Intermediates for α1, β1, and γ1 Chains of Laminin. ANNALS OF INTEGRATIVE MOLECULAR MEDICINE 2019; 1:48-60. [PMID: 31663081 PMCID: PMC6818727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
De novo production of RNA on RNA template, a process known as RNA-dependent RNA synthesis, RdRs, and the enzymatic activity conducting it, RNA-dependent RNA polymerase, RdRp, were initially considered to be exclusively virus-specific. Eventually, however, the occurrence of RdRs and the ubiquitous presence of conventional RdRp were demonstrated in numerous eukaryotic organisms. The evidence that the enzymatic machinery capable of RdRs is present in mammalian cells was derived from studies of viruses, such as hepatitis delta virus, HDV, that do not encode RdRp yet undergo a robust RNA replication once inside the mammalian host; thus firmly establishing its occurrence and functionality. Moreover, it became clear that RdRp activity, apparently in a non-conventional form, is constitutively present in most, if not in all, mammalian cells. Because such activity was shown to produce short transcripts, given its apparent involvement in RNA interference phenomena, and because double-stranded RNA is known to trigger cellular responses leading to its degradation, it was generally assumed that its role in mammalian cells is restricted to a regulatory function. However, at the same time, an enzymatic activity capable of generating complete antisense RNA complements of mRNAs was discovered in mammalian cells undergoing terminal differentiation. Moreover, observations of widespread synthesis of antisense RNAs initiating at the 3'poly(A) of mRNAs in human cells suggested an extensive cellular utilization of mammalian RdRp. These results led to the development of a model of RdRp-facilitated and antisense RNA-mediated amplification of mammalian mRNA. Recent detection of the major model-predicted identifiers, chimeric RNA intermediates containing both sense and antisense RNA strands covalently joined in a rigorously predicted and uniquely defined manner, as well as the identification of a putative chimeric RNA end product of this process, validated the proposed model. The results corroborating mammalian RNA-dependent mRNA amplification were obtained in vivo with cells undergoing terminal erythroid differentiation and programmed for only a short survival span. This raises a question of whether mammalian RNA-dependent mRNA amplification is a specialized occurrence limited to extreme circumstances of terminal differentiation or a general physiological phenomenon. The present study addresses this question by testing for the occurrence of RNA-dependent amplification of mRNA encoding extracellular matrix proteins abundantly produced throughout the tissue and organ development and homeostasis, an exceptionally revealing indicator of the range and scope of this phenomenon. We report here the detection of major identifiers of RNA-dependent amplification of mRNA encoding α1, β1, and γ1 chains of laminin in mouse tissues producing large quantities of extracellular matrix proteins. The results obtained warrant reinterpretation of the mechanisms involved in ubiquitous and abundant production and deposition of extracellular matrix proteins, confirm the occurrence of mammalian RNA-dependent mRNA amplification as a new mode of genomic protein-encoding information transfer, and establish it as a general physiological phenomenon.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of
Dental Medicine, USA
| | - Sophia Rits
- Division of Molecular Medicine, Children’s Hospital,
Boston, USA
- Department of Biological Chemistry and Molecular
Pharmacology, Harvard Medical School, USA
| | - Bjorn R Olsen
- Department of Developmental Biology, Harvard School of
Dental Medicine, USA
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220
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Rits S, Olsen BR, Volloch V. Protein-Encoding RNA to RNA Information Transfer in Mammalian Cells: RNA-dependent mRNA Amplification. Identification of Chimeric RNA Intermediates and Putative RNA End Products. ANNALS OF INTEGRATIVE MOLECULAR MEDICINE 2019; 1:23-47. [PMID: 31656957 PMCID: PMC6814175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Our initial unidirectional understanding of the flow of protein-encoding genetic information, DNA to RNA to protein, a process defined as the "Central Dogma of Molecular Biology" and usually depicted as a downward arrow, was eventually amended to account for the "vertical" information back-flow from RNA to DNA, reverse transcription, and for its "horizontal" side-flow from RNA to RNA, RNA-dependent RNA synthesis, RdRs. These processes, both potentially leading to protein production, were assumed to be strictly virus-specific. However, whereas this presumption might be true for the former, it became apparent that the cellular enzymatic machinery for the later, a conventional RNA-dependent RNA polymerase activity, RdRp, is ubiquitously present and RdRs regularly occurs in eukaryotes. The strongest evidence for the occurrence and functionality of RdRp activity in mammalian cells comes from viruses, such as hepatitis delta virus, HDV, that do not encode RdRp yet undergo a robust RNA replication once inside the host. Eventually, it became clear that RdRp activity, apparently in a non-conventional form, is constitutively present in most, if not in all, mammalian cells. Because such activity was shown to produce short transcripts, because of its apparent involvement in RNA interference phenomena, and because double-stranded RNA is known to trigger cellular responses leading to its degradation, it was generally assumed that its role in mammalian cells is restricted to a regulatory function. However, at the same time, an enzymatic activity capable of generating complete antisense RNA complements of mRNAs was discovered in mammalian cells undergoing terminal differentiation. Moreover, observations of widespread synthesis of antisense RNA initiating at the 3'poly(A) of mRNAs in human cells suggested an extensive cellular utilization of mammalian RdRp. These results led to the development of a model of RdRp-facilitated and antisense RNA-mediated amplification of mammalian mRNA. Here, we report the in vivo detection in cells undergoing terminal erythroid differentiation of the major model-predicted identifiers of such a process, a chimeric double-stranded/pinhead-structured intermediates containing both sense and antisense RNA strands covalently joined in a rigorously predicted and uniquely defined manner. We also report the identification of the putative chimeric RNA end product of mRNA amplification. It is heavily modified, uniformly truncated, yet retains the intact coding region, and terminates with the OH group at both ends; its massive cellular amount is unprecedented for a conventional mRNA transcription product and it translates into polypeptides indistinguishable from the translation product of conventional mRNA. Moreover, we describe the occurrence of the second Tier of mammalian RNA-dependent mRNA amplification, a physiologically occurring, RdRp-driven intracellular PCR process, "iPCR", and report the detection of its distinct RNA end products. Whether mammalian mRNA amplification is a specialized occurrence limited to extreme circumstances of terminal differentiation in cells programmed for only a short survival span or a general physiological phenomenon was answered in the companion article Volloch et al. Ann Integr Mol Med. 2019;1(1):1004. by the detection of major identifiers of this process for mRNA encoding α1, β1, and γ1 chains of laminin, a major extracellular matrix protein abundantly produced throughout the tissue and organ development and homeostasis and an exceptionally revealing indicator of the range and scope of this phenomenon. The results obtained introduce the occurrence of RNA-dependent mRNA amplification as a new mode of genomic protein-encoding information transfer in mammalian cells and establish it as a general physiological phenomenon.
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Affiliation(s)
- Sophia Rits
- Division of Molecular Medicine, Children’s Hospital, Boston, USA
- Deptartment of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, USA
| | - Bjorn R. Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
| | - Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
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221
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Janapala Y, Preiss T, Shirokikh NE. Control of Translation at the Initiation Phase During Glucose Starvation in Yeast. Int J Mol Sci 2019; 20:E4043. [PMID: 31430885 PMCID: PMC6720308 DOI: 10.3390/ijms20164043] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/10/2019] [Accepted: 08/15/2019] [Indexed: 12/13/2022] Open
Abstract
Glucose is one of the most important sources of carbon across all life. Glucose starvation is a key stress relevant to all eukaryotic cells. Glucose starvation responses have important implications in diseases, such as diabetes and cancer. In yeast, glucose starvation causes rapid and dramatic effects on the synthesis of proteins (mRNA translation). Response to glucose deficiency targets the initiation phase of translation by different mechanisms and with diverse dynamics. Concomitantly, translationally repressed mRNAs and components of the protein synthesis machinery may enter a variety of cytoplasmic foci, which also form with variable kinetics and may store or degrade mRNA. Much progress has been made in understanding these processes in the last decade, including with the use of high-throughput/omics methods of RNA and RNA:protein detection. This review dissects the current knowledge of yeast reactions to glucose starvation systematized by the stage of translation initiation, with the focus on rapid responses. We provide parallels to mechanisms found in higher eukaryotes, such as metazoans, for the most critical responses, and point out major remaining gaps in knowledge and possible future directions of research on translational responses to glucose starvation.
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Affiliation(s)
- Yoshika Janapala
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia.
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia.
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222
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Hernández G, Osnaya VG, Pérez-Martínez X. Conservation and Variability of the AUG Initiation Codon Context in Eukaryotes. Trends Biochem Sci 2019; 44:1009-1021. [PMID: 31353284 DOI: 10.1016/j.tibs.2019.07.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 06/22/2019] [Accepted: 07/02/2019] [Indexed: 01/30/2023]
Abstract
Selection of the translation initiation site (TIS) is a crucial step during translation. In the 1980s Marylin Kozak performed key studies on vertebrate mRNAs to characterize the optimal TIS consensus sequence, the Kozak motif. Within this motif, conservation of nucleotides in crucial positions, namely a purine at -3 and a G at +4 (where the A of the AUG is numbered +1), is essential for TIS recognition. Ever since its characterization the Kozak motif has been regarded as the optimal sequence to initiate translation in all eukaryotes. We revisit here published in silico data on TIS consensus sequences, as well as experimental studies from diverse eukaryotic lineages, and propose that, while the -3A/G position is universally conserved, the remaining variability of the consensus sequences enables their classification as optimal, strong, and moderate TIS sequences.
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Affiliation(s)
- Greco Hernández
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Avenue, Tlalpan, 14080 Mexico City, Mexico.
| | - Vincent G Osnaya
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Avenue, Tlalpan, 14080 Mexico City, Mexico
| | - Xochitl Pérez-Martínez
- Department of Molecular Genetics, Cell Physiology Institute (Instituto de Fisiología Celular), Universidad Nacional Autónoma de México (UNAM), 04510 Mexico City, Mexico
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223
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Abstract
The universal triple-nucleotide genetic code is often viewed as a given, randomly selected through evolution. However, as summarized in this article, many observations and deductions within structural and thermodynamic frameworks help to explain the forces that must have shaped the code during the early evolution of life on Earth.
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224
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Abstract
Members of the MYC family of oncogenes are master regulators of mRNA translation. In this issue of JEM, Singh et al. (https://doi.org/10.1084/jem.20181726) demonstrate that c-Myc governs protein synthesis in lymphoma cells by interfering with SRSF1- and RBM42-mediated suppression of mRNA translation and by altering selection of translation initiation sites.
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Affiliation(s)
- Marie Cargnello
- Cancer Research Center of Toulouse, Institut National de la Santé et de la Recherche Médicale UMR 1037, University of Toulouse, Toulouse, France
| | - Ivan Topisirovic
- Lady Davis Institute, Sir Mortimor B. Davis Jewish General Hospital, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, Division of Experimental Medicine and Department of Biochemistry, McGill University, Montreal, Quebec, Canada
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225
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Chen HH, Tarn WY. uORF-mediated translational control: recently elucidated mechanisms and implications in cancer. RNA Biol 2019; 16:1327-1338. [PMID: 31234713 DOI: 10.1080/15476286.2019.1632634] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Protein synthesis is tightly regulated, and its dysregulation can contribute to the pathology of various diseases, including cancer. Increased or selective translation of mRNAs can promote cancer cell proliferation, metastasis and tumor expansion. Translational control is one of the most important means for cells to quickly adapt to environmental stresses. Adaptive translation involves various alternative mechanisms of translation initiation. Upstream open reading frames (uORFs) serve as a major regulator of stress-responsive translational control. Since recent advances in omics technologies including ribo-seq have expanded our knowledge of translation, we discuss emerging mechanisms for uORF-mediated translation regulation and its impact on cancer cell biology. A better understanding of dysregulated translational control of uORFs in cancer would facilitate the development of new strategies for cancer therapy.
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Affiliation(s)
- Hung-Hsi Chen
- Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
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226
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Chen L, He J, Zhou J, Xiao Z, Ding N, Duan Y, Li W, Sun LQ. EIF2A promotes cell survival during paclitaxel treatment in vitro and in vivo. J Cell Mol Med 2019; 23:6060-6071. [PMID: 31211507 PMCID: PMC6714208 DOI: 10.1111/jcmm.14469] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 04/25/2019] [Accepted: 05/17/2019] [Indexed: 12/14/2022] Open
Abstract
The integrated stress response (ISR) is critical for cancer cell survival during stress stimuli and has been implicated in the resistance to cancer therapeutics, in which the mechanism, however, is poorly understood. Here, we showed that paclitaxel, the major chemotherapy drug for breast cancer, induced ISR and phosphorylated ser51 residue of EIF2S1 by EIF2AK3 and EIF2AK4. When exposed to paclitaxel, cancer cells activated the EIF2AK3/EIF2AK4-pEIF2S1-ATF4 axis and maintained redox homoeostasis by inducing expression of the major antioxidant enzymes HMOX1, SHMT2 and SLC7A11. Paclitaxel-mediated cell death was significantly increased following loss of ISR or ATF4 expression. This sensitizing effect could be partially rescued by Trolox, a ROS scavenger. We demonstrated that the alternative initiation factor EIF2A was essential for cancer cell survival after paclitaxel-mediated ISR both in vitro and in vivo. Moreover, patients with breast cancer exhibited higher ISR after chemotherapy, and the elevated mRNA levels of HMOX1, SHMT2 and EIF2A were correlated with poor prognosis. Collectively, our findings reveal a novel mechanism for paclitaxel resistance and suggest that targeting EIF2A combined with ISR agonist may be a potential treatment regimen to overcome drug resistance for breast cancer.
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Affiliation(s)
- Lin Chen
- Center for Molecular Medicine, Xiangya Hospital, Collaborative Innovation Center for Cancer Medicine, Central South University, Changsha, Hunan, P.R. China.,Key Laboratory of Molecular Radiation Oncology, Changsha, Hunan, P.R. China
| | - Jiang He
- Center for Molecular Medicine, Xiangya Hospital, Collaborative Innovation Center for Cancer Medicine, Central South University, Changsha, Hunan, P.R. China.,Key Laboratory of Molecular Radiation Oncology, Changsha, Hunan, P.R. China
| | - Jianhua Zhou
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Zhi Xiao
- Department of Breast Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Nianhua Ding
- Center for Molecular Medicine, Xiangya Hospital, Collaborative Innovation Center for Cancer Medicine, Central South University, Changsha, Hunan, P.R. China
| | - Yumei Duan
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Wenzheng Li
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Lun-Quan Sun
- Center for Molecular Medicine, Xiangya Hospital, Collaborative Innovation Center for Cancer Medicine, Central South University, Changsha, Hunan, P.R. China.,Key Laboratory of Molecular Radiation Oncology, Changsha, Hunan, P.R. China
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227
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Kearse MG, Goldman DH, Choi J, Nwaezeapu C, Liang D, Green KM, Goldstrohm AC, Todd PK, Green R, Wilusz JE. Ribosome queuing enables non-AUG translation to be resistant to multiple protein synthesis inhibitors. Genes Dev 2019; 33:871-885. [PMID: 31171704 PMCID: PMC6601509 DOI: 10.1101/gad.324715.119] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/24/2019] [Indexed: 02/05/2023]
Abstract
Here, Kearse et al. used start codon-specific reporters and ribosome profiling to characterize how translation from non-AUG start codons responds to protein synthesis inhibitors in human cells. Their data indicate that ribosome queuing enables mRNAs with poor initiation context—namely, those with non-AUG start codons—to be resistant to pharmacological translation inhibitors at concentrations that robustly inhibit global translation. Aberrant translation initiation at non-AUG start codons is associated with multiple cancers and neurodegenerative diseases. Nevertheless, how non-AUG translation may be regulated differently from canonical translation is poorly understood. Here, we used start codon-specific reporters and ribosome profiling to characterize how translation from non-AUG start codons responds to protein synthesis inhibitors in human cells. These analyses surprisingly revealed that translation of multiple non-AUG-encoded reporters and the endogenous GUG-encoded DAP5 (eIF4G2/p97) mRNA is resistant to cycloheximide (CHX), a translation inhibitor that severely slows but does not completely abrogate elongation. Our data suggest that slowly elongating ribosomes can lead to queuing/stacking of scanning preinitiation complexes (PICs), preferentially enhancing recognition of weak non-AUG start codons. Consistent with this model, limiting PIC formation or scanning sensitizes non-AUG translation to CHX. We further found that non-AUG translation is resistant to other inhibitors that target ribosomes within the coding sequence but not those targeting newly initiated ribosomes. Together, these data indicate that ribosome queuing enables mRNAs with poor initiation context—namely, those with non-AUG start codons—to be resistant to pharmacological translation inhibitors at concentrations that robustly inhibit global translation.
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Affiliation(s)
- Michael G Kearse
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Daniel H Goldman
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Jiou Choi
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Chike Nwaezeapu
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Dongming Liang
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Aaron C Goldstrohm
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109, USA.,Veterans Affairs Medical Center, Ann Arbor, Michigan 48105, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
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228
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Caballero M, Wegrzyn J. gFACs: Gene Filtering, Analysis, and Conversion to Unify Genome Annotations Across Alignment and Gene Prediction Frameworks. GENOMICS, PROTEOMICS & BIOINFORMATICS 2019; 17:305-310. [PMID: 31437583 PMCID: PMC6818179 DOI: 10.1016/j.gpb.2019.04.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/21/2019] [Accepted: 04/29/2019] [Indexed: 11/26/2022]
Abstract
Published genomes frequently contain erroneous gene models that represent issues associated with identification of open reading frames, start sites, splice sites, and related structural features. The source of these inconsistencies is often traced back to integration across text file formats designed to describe long read alignments and predicted gene structures. In addition, the majority of gene prediction frameworks do not provide robust downstream filtering to remove problematic gene annotations, nor do they represent these annotations in a format consistent with current file standards. These frameworks also lack consideration for functional attributes, such as the presence or absence of protein domains that can be used for gene model validation. To provide oversight to the increasing number of published genome annotations, we present a software package, the Gene Filtering, Analysis, and Conversion (gFACs), to filter, analyze, and convert predicted gene models and alignments. The software operates across a wide range of alignment, analysis, and gene prediction files with a flexible framework for defining gene models with reliable structural and functional attributes. gFACs supports common downstream applications, including genome browsers, and generates extensive details on the filtering process, including distributions that can be visualized to further assess the proposed gene space. gFACs is freely available and implemented in Perl with support from BioPerl libraries at https://gitlab.com/PlantGenomicsLab/gFACs.
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Affiliation(s)
- Madison Caballero
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.
| | - Jill Wegrzyn
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.
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229
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Rodríguez-Jiménez C, Gómez-Coronado D, Frías Vargas M, Cerrato F, Lahoz C, Saban-Ruiz J, González-Nieto D, Lasunción MA, Mostaza JM, Rodríguez-Nóvoa S. A new variant (c.1A>G) in LDLRAP1 causing autosomal recessive hypercholesterolemia: Characterization of the defect and response to PCSK9 inhibition. Atherosclerosis 2019; 284:223-229. [PMID: 30777337 DOI: 10.1016/j.atherosclerosis.2019.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/12/2018] [Accepted: 01/10/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND AIMS Autosomal recessive hypercholesterolemia (ARH) is a rare disorder caused by mutations in LDLRAP1, which impairs internalization of hepatic LDL receptor (LDLR). ARH patients respond relatively well to statins or the combination of statins and Ezetimibe, but scarce and variable data on treatment with PCSK9 inhibitors is available. We aimed to identify and characterize the defect in a hypercholesterolemic patient with premature cardiovascular disease and determine the response to lipid-lowering treatment. METHODS AND RESULTS Gene sequencing revealed a homozygous c.1A > G:p.? variant in LDLRAP1. Primary lymphocytes were isolated from the ARH patient, one control and two LDLR-defective subjects, one LDLR:p.(Cys352Ser) heterozygote and one LDLR:p.(Asn825Lys) homozygote. The patient had undetectable full-length ARH protein by Western blotting, but expressed a lower-than-normal molecular weight peptide. LDLR activity was measured by flow cytometry, which showed that LDL binding and uptake were reduced in lymphocytes from the ARH patient as compared to control lymphocytes, but were slightly higher than in those from the LDLR:p.(Cys352Ser) heterozygote. Despite the analogous internalization defect predicted in ARH and homozygous LDLR:p.(Asn825Lys) lymphocytes, LDL uptake was higher in the former than in the latter. LDL-cholesterol levels were markedly reduced by the successive therapy with Atorvastatin and Atorvastatin plus Ezetimibe, and the addition of Evolocumab biweekly decreased LDL-cholesterol by a further 39%. CONCLUSIONS The LDLRAP1:c.1A > G variant is associated with the appearance of an N-terminal truncated ARH protein and to reduced, although still significant, LDLR activity in lymphocytes. Residual LDLR activity may be relevant for the substantial response of the patient to Evolocumab.
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Affiliation(s)
- Carmen Rodríguez-Jiménez
- Department of Genetics of Metabolic Diseases, Institute of Medical & Molecular Genetics (INGEMM), Hospital Universitario La Paz, IdiPAZ, Madrid, Spain
| | - Diego Gómez-Coronado
- Department of Biochemistry-Research, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Spain
| | | | - Francisca Cerrato
- Department of Biochemistry-Research, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - Carlos Lahoz
- Department of Internal Medicine, Hospital Carlos III-La Paz, Madrid, Spain
| | - Jose Saban-Ruiz
- Endothelium and Cardiometabolic Medicine Unit, Department of Internal Medicine, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Daniel González-Nieto
- Center for Biomedical Technology, Photonics Technology and Bioengineering Department, ETSI Telecomunicaciones, Universidad Politécnica de Madrid, and CIBERBBN, Spain
| | - Miguel A Lasunción
- Department of Biochemistry-Research, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Spain
| | - José M Mostaza
- Department of Internal Medicine, Hospital Carlos III-La Paz, Madrid, Spain
| | - Sonia Rodríguez-Nóvoa
- Department of Genetics of Metabolic Diseases, Institute of Medical & Molecular Genetics (INGEMM), Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
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230
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Goodman LD, Prudencio M, Srinivasan AR, Rifai OM, Lee VMY, Petrucelli L, Bonini NM. eIF4B and eIF4H mediate GR production from expanded G4C2 in a Drosophila model for C9orf72-associated ALS. Acta Neuropathol Commun 2019; 7:62. [PMID: 31023341 PMCID: PMC6485101 DOI: 10.1186/s40478-019-0711-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/25/2019] [Indexed: 01/09/2023] Open
Abstract
The discovery of an expanded (GGGGCC)n repeat (termed G4C2) within the first intron of C9orf72 in familial ALS/FTD has led to a number of studies showing that the aberrant expression of G4C2 RNA can produce toxic dipeptides through repeat-associated non-AUG (RAN-) translation. To reveal canonical translation factors that impact this process, an unbiased loss-of-function screen was performed in a G4C2 fly model that maintained the upstream intronic sequence of the human gene and contained a GFP tag in the GR reading frame. 11 of 48 translation factors were identified that impact production of the GR-GFP protein. Further investigations into two of these, eIF4B and eIF4H, revealed that downregulation of these factors reduced toxicity caused by the expression of expanded G4C2 and reduced production of toxic GR dipeptides from G4C2 transcripts. In patient-derived cells and in post-mortem tissue from ALS/FTD patients, eIF4H was found to be downregulated in cases harboring the G4C2 mutation compared to patients lacking the mutation and healthy individuals. Overall, these data define eIF4B and eIF4H as disease modifiers whose activity is important for RAN-translation of the GR peptide from G4C2-transcripts.
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Affiliation(s)
- Lindsey D. Goodman
- 0000 0004 1936 8972grid.25879.31Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Mercedes Prudencio
- 0000 0004 0443 9942grid.417467.7Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Ananth R. Srinivasan
- 0000 0004 1936 8972grid.25879.31Department of Biology, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Olivia M. Rifai
- 0000 0004 1936 8972grid.25879.31Department of Biology, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Virginia M.-Y. Lee
- 0000 0004 1936 8972grid.25879.31Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Leonard Petrucelli
- 0000 0004 0443 9942grid.417467.7Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Nancy M. Bonini
- 0000 0004 1936 8972grid.25879.31Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA ,0000 0004 1936 8972grid.25879.31Department of Biology, University of Pennsylvania, Philadelphia, PA 19104 USA
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231
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Function and Evolution of Upstream ORFs in Eukaryotes. Trends Biochem Sci 2019; 44:782-794. [PMID: 31003826 DOI: 10.1016/j.tibs.2019.03.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/08/2019] [Accepted: 03/19/2019] [Indexed: 12/18/2022]
Abstract
There is growing interest in the role of translational regulation in cellular homeostasis during organismal development. Translation initiation is the rate-limiting step in mRNA translation and is central to translational regulation. Upstream open reading frames (uORFs) are regulatory elements that are prevalent in eukaryotic mRNAs. uORFs modulate the translation initiation rate of downstream coding sequences (CDSs) by sequestering ribosomes. Over the past several years, genome-wide studies have revealed the widespread regulatory functions of uORFs in different species in different biological contexts. Here, we review the current understanding of uORF-mediated translational regulation from the perspective of functional and evolutionary genomics and address remaining gaps that deserve further study.
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232
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Martins RP, Malbert-Colas L, Lista MJ, Daskalogianni C, Apcher S, Pla M, Findakly S, Blondel M, Fåhraeus R. Nuclear processing of nascent transcripts determines synthesis of full-length proteins and antigenic peptides. Nucleic Acids Res 2019; 47:3086-3100. [PMID: 30624716 PMCID: PMC6451098 DOI: 10.1093/nar/gky1296] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/23/2018] [Accepted: 12/18/2018] [Indexed: 01/19/2023] Open
Abstract
Peptides presented on major histocompatibility (MHC) class I molecules form an essential part of the immune system's capacity to detect virus-infected or transformed cells. Earlier works have shown that pioneer translation peptides (PTPs) for the MHC class I pathway are as efficiently produced from introns as from exons, or from mRNAs targeted for the nonsense-mediated decay pathway. The production of PTPs is a target for viral immune evasion but the underlying molecular mechanisms that govern this non-canonical translation are unknown. Here, we have used different approaches to show how events taking place on the nascent transcript control the synthesis of PTPs and full-length proteins. By controlling the subcellular interaction between the G-quadruplex structure (G4) of a gly-ala encoding mRNA and nucleolin (NCL) and by interfering with mRNA maturation using multiple approaches, we demonstrate that antigenic peptides derive from a nuclear non-canonical translation event that is independently regulated from the synthesis of full-length proteins. Moreover, we show that G4 are exploited to control mRNA localization and translation by distinguishable mechanisms that are targets for viral immune evasion.
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Affiliation(s)
| | | | - María José Lista
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France
| | - Chrysoula Daskalogianni
- Université Paris 7, Inserm, UMR 1162, Paris, France
- ICCVS, University of Gdańsk, Science, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Sebastien Apcher
- Institut Gustave Roussy, Université Paris Sud, UMR 1015, Villejuif, France
| | - Marika Pla
- Université Paris 7, IUH, Inserm, UMR-S-1131, Paris, France
| | | | - Marc Blondel
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France
| | - Robin Fåhraeus
- Université Paris 7, Inserm, UMR 1162, Paris, France
- ICCVS, University of Gdańsk, Science, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
- Department of Medical Biosciences, Umeå University, Umeå, Sweden
- RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic
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233
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Sanz MA, Almela EG, García-Moreno M, Marina AI, Carrasco L. A viral RNA motif involved in signaling the initiation of translation on non-AUG codons. RNA (NEW YORK, N.Y.) 2019; 25:431-452. [PMID: 30659060 PMCID: PMC6426287 DOI: 10.1261/rna.068858.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Noncanonical translation, and particularly initiation on non-AUG codons, are frequently used by viral and cellular mRNAs during virus infection and disease. The Sindbis virus (SINV) subgenomic mRNA (sgRNA) constitutes a unique model system to analyze the translation of a capped viral mRNA without the participation of several initiation factors. Moreover, sgRNA can initiate translation even when the AUG initiation codon is replaced by other codons. Using SINV replicons, we examined the efficacy of different codons in place of AUG to direct the synthesis of the SINV capsid protein. The substitution of AUG by CUG was particularly efficient in promoting the incorporation of leucine or methionine in similar percentages at the amino terminus of the capsid protein. Additionally, valine could initiate translation when the AUG is replaced by GUG. The ability of sgRNA to initiate translation on non-AUG codons was dependent on the integrity of a downstream stable hairpin (DSH) structure located in the coding region. The structural requirements of this hairpin to signal the initiation site on the sgRNA were examined in detail. Of interest, a virus bearing CUG in place of AUG in the sgRNA was able to infect cells and synthesize significant amounts of capsid protein. This virus infects the human haploid cell line HAP1 and the double knockout variant that lacks eIF2A and eIF2D. Collectively, these findings indicate that leucine-tRNA or valine-tRNA can participate in the initiation of translation of sgRNA by a mechanism dependent on the DSH. This mechanism does not involve the action of eIF2, eIF2A, or eIF2D.
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MESH Headings
- Capsid Proteins/biosynthesis
- Capsid Proteins/genetics
- Cell Line, Tumor
- Codon, Initiator/genetics
- Codon, Initiator/metabolism
- Eukaryotic Initiation Factor-2/deficiency
- Eukaryotic Initiation Factor-2/genetics
- Fibroblasts/metabolism
- Fibroblasts/virology
- Gene Expression Regulation
- Haploidy
- Host-Pathogen Interactions/genetics
- Humans
- Inverted Repeat Sequences
- Leucine/genetics
- Leucine/metabolism
- Methionine/genetics
- Methionine/metabolism
- Nucleic Acid Conformation
- Protein Biosynthesis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Transfer, Leu/genetics
- RNA, Transfer, Leu/metabolism
- RNA, Transfer, Val/genetics
- RNA, Transfer, Val/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Replicon
- Signal Transduction/genetics
- Sindbis Virus/genetics
- Sindbis Virus/metabolism
- Valine/genetics
- Valine/metabolism
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Affiliation(s)
- Miguel Angel Sanz
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Esther González Almela
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Manuel García-Moreno
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Ana Isabel Marina
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Luis Carrasco
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
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Antony A C, Ram AK, Dutta K, Alone PV. Ribosomal mutation in helix 32 of 18S rRNA alters fidelity of eukaryotic translation start site selection. FEBS Lett 2019; 593:852-867. [PMID: 30900251 DOI: 10.1002/1873-3468.13369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 11/09/2022]
Abstract
The 40S ribosome plays a critical role in start codon selection. To gain insights into the role of its 18S rRNA in start codon selection, a suppressor screen was performed that suppressed the preferential UUG start codon recognition (Suppressor of initiation codon: Sui- phenotype) associated with the eIF5G31R mutant. The C1209U mutation in helix h32 of 18S rRNA was found to suppress the Sui- and Gcn- (failure to derepress GCN4 expression) phenotype of the eIF5G31R mutant. The C1209U mutation suppressed Sui- and Gcd- (constitutive derepression of GCN4 expression) phenotype of eIF2βS264Y , eIF1K60E , and eIF1A-ΔC mutation. We propose that the C1209U mutation in 40S ribosomal may perturb the premature head rotation in 'Closed/PIN ' state and enhance the stringency of translation start site selection.
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Affiliation(s)
- Charles Antony A
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Anup Kumar Ram
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Kalloly Dutta
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Pankaj V Alone
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
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235
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Xu C, Park JK, Zhang J. Evidence that alternative transcriptional initiation is largely nonadaptive. PLoS Biol 2019; 17:e3000197. [PMID: 30883542 PMCID: PMC6438578 DOI: 10.1371/journal.pbio.3000197] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/28/2019] [Accepted: 03/12/2019] [Indexed: 12/22/2022] Open
Abstract
Alternative transcriptional initiation (ATI) refers to the frequent observation that one gene has multiple transcription start sites (TSSs). Although this phenomenon is thought to be adaptive, the specific advantage is rarely known. Here, we propose that each gene has one optimal TSS and that ATI arises primarily from imprecise transcriptional initiation that could be deleterious. This error hypothesis predicts that (i) the TSS diversity of a gene reduces with its expression level; (ii) the fractional use of the major TSS increases, but that of each minor TSS decreases, with the gene expression level; and (iii) cis-elements for major TSSs are selectively constrained, while those for minor TSSs are not. By contrast, the adaptive hypothesis does not make these predictions a priori. Our analysis of human and mouse transcriptomes confirms each of the three predictions. These and other findings strongly suggest that ATI predominantly results from molecular errors, requiring a major revision of our understanding of the precision and regulation of transcription. The transcription of a gene may start from one of several transcription start sites, a phenomenon known as alternative transcriptional initiation. Contrary to common belief, this study shows that variation of the transcription start site of a given gene is nonadaptive and is largely attributable to transcriptional initiation error that is typically deleterious. Multiple surveys of transcriptional initiation showed that mammalian genes typically have multiple transcription start sites such that transcription is initiated from any one of these sites. Many researchers believe that this phenomenon is adaptive because it allows production of multiple transcripts, from the same gene, that potentially vary in function or post-transcriptional regulation. Nevertheless, it is also possible that each gene has only one optimal transcription start site and that alternative transcriptional initiation arises primarily from molecular errors that are slightly deleterious. This error hypothesis makes a series of predictions about the amount of transcription start site diversity per gene, relative uses of the various start sites of a gene, among-tissue and across-species differences in start site usage, and the evolutionary conservation of cis-regulatory elements of various start sites, all of which are verified in our analyses of genome-wide transcription start site data from the human and mouse. These findings strongly suggest that alternative transcriptional initiation largely reflects molecular errors instead of molecular adaptations and require a rethink of the precision and regulation of transcription.
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Affiliation(s)
- Chuan Xu
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Joong-Ki Park
- Division of EcoScience, Ewha Womans University, Seoul, Republic of Korea
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Volloch V, Rits-Volloch S. News from Mars: Two-Tier Paradox, Intracellular PCR, Chimeric Junction Shift, Dark Matter mRNA and Other Remarkable Features of Mammalian RNA-Dependent mRNA Amplification. Implications for Alzheimer's Disease, RNA-Based Vaccines and mRNA Therapeutics. ACTA ACUST UNITED AC 2019; 2:131-173. [PMID: 33942036 DOI: 10.33597/aimm.02-1009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Molecular Biology, a branch of science established to examine the flow of information from "letters" encrypted into DNA structure to functional proteins, was initially defined by a concept of DNA-to-RNA-to-Protein information movement, a notion termed the Central Dogma of Molecular Biology. RNA-dependent mRNA amplification, a novel mode of eukaryotic protein-encoding RNA-to-RNA-to-Protein genomic information transfer, constitutes the extension of the Central Dogma in the context of mammalian cells. It was shown to occur in cellular circumstances requiring exceptionally high levels of production of specific polypeptides, e.g. globin chains during erythroid differentiation or defined secreted proteins in the context of extracellular matrix deposition. Its potency is reflected in the observed cellular levels of the resulting amplified mRNA product: At the peak of the erythroid differentiation, for example, the amount of globin mRNA produced in the amplification pathway is about 1500-fold higher than the amount of its conventionally generated counterpart in the same cells. The cellular enzymatic machinery at the core of this process, RNA-dependent RNA polymerase activity (RdRp), albeit in a non-conventional form, was shown to be constitutively and ubiquitously present, and RNA-dependent RNA synthesis (RdRs) appeared to regularly occur, in mammalian cells. Under most circumstances, the mammalian RdRp activity produces only short antisense RNA transcripts. Generation of complete antisense RNA transcripts and amplification of mRNA molecules require the activation of inducible components of the mammalian RdRp complex. The mechanism of such activation is not clear. The present article suggests that it is triggered by a variety of cellular stresses and occurs in the context of stress responses in general and within the framework of the integrated stress response (ISR) in particular. In this process, various cellular stresses activate, in a stress type-specific manner, defined members of the mammalian translation initiation factor 2α, eIF2α, kinase family: PKR, GCN2, PERK and HRI. Any of these kinases, in an activated form, phosphorylates eIF2α. This results in suppression of global cellular protein synthesis but also in activation of expression of select group of transcription factors including ATF4, ATF5 and CHOP. These transcription factors either function as inducible components of the RdRp complex or enable their expression. The assembly of the competent RdRp complex activates mammalian RNA-dependent mRNA amplification, which appears to be a two-tier process. Tier One is a "chimeric" pathway, named so because it results in an amplified chimeric mRNA molecule containing a fragment of the antisense RNA strand at its 5' terminus. Tier Two further amplifies one of the two RNA end products of the chimeric pathway and constitutes the physiologically occurring intracellular polymerase chain reaction, iPCR. Depending on the structure of the initial mRNA amplification progenitor, the chimeric pathway, Tier One, may result in multiple outcomes including chimeric mRNA that produces either a polypeptide identical to the original, conventional mRNA progenitor-encoded protein or only its C-terminal fragment, CTF. The chimeric RNA end product of Tier One may also produce a polypeptide that is non-contiguously encoded in the genome, activate translation from an open reading frame, which is "silent" in a conventionally transcribed mRNA, or initiate an abortive translation. In sharp contrast, regardless of the outcome of Tier One, the mRNA end product of Tier Two of mammalian mRNA amplification, the iPCR pathway, always produces a polypeptide identical to a conventional mRNA progenitor-encoded protein. This discordance is referred to as the Two-Tier Paradox and discussed in detail in the present article. On the other hand, both Tiers are similar in that they result in heavily modified mRNA molecules resistant to reverse transcription, undetectable by reverse transcription-based methods of sequencing and therefore constituting a proverbial "Dark Matter" mRNA, despite being highly ubiquitous. It appears that in addition to their other functions, the modifications of the amplified mRNA render it compatible, unlike the bulk of cellular mRNA, with phosphorylated eIF2α in translation, implying that in addition to being extraordinarily abundant due to the method of its generation, amplified mRNA is also preferentially translated under the ISR conditions, thus augmenting the efficiency of the amplification process. The vital importance of powerful mechanisms of amplification of protein-encoding genomic information in normal physiology is self-evident. Their malfunctions or misuse appear to be associated with two types of abnormalities, the deficiency of a protein normally produced by these mechanisms and the mRNA amplification-mediated overproduction of a protein normally not generated by such a process. Certain classes of beta-thalassemia exemplify the first type, whereas the second type is represented by overproduction of beta-amyloid in Alzheimer's disease. Moreover, the proposed mechanism of Alzheimer's disease allows a crucial and verifiable prediction, namely that the disease-causing intraneuronally retained variant of beta-amyloid differs from that produced conventionally by βAPP proteolysis in that it contains the additional methionine or acetylated methionine at its N-terminus. Because of its extraordinary evidential value as a natural reporter of the mRNA amplification pathway, this feature, if proven, would, arguably, constitute the proverbial Holy Grail not only for Alzheimer's disease but also for the mammalian RNA-dependent mRNA amplification field in general. Both examples are discussed in detail in the present article, which summarizes and systematizes our current understanding of the field and describes two categories of reporter constructs, one for the chimeric Tier of mRNA amplification, another for the iPCR pathway; both reporter types are essential for elucidating underlying molecular mechanisms. It also suggests, in light of the recently demonstrated feasibility of RNA-based vaccines, that the targeted intracellular amplification of exogenously introduced amplification-eligible antigen-encoding mRNAs via the induced or naturally occurring RNA-dependent mRNA amplification pathway could be of substantial benefit in triggering a fast and potent immune response and instrumental in the development of future vaccines. Similar approaches can also be effective in achieving efficient and sustained expression of exogenous mRNA in mRNA therapeutics.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children's Hospital, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, USA
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237
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Wang J, Kinch LN, Denard B, Lee CE, Esmaeilzadeh Gharehdaghi E, Grishin N, Ye J. Identification of residues critical for topology inversion of the transmembrane protein TM4SF20 through regulated alternative translocation. J Biol Chem 2019; 294:6054-6061. [PMID: 30808712 DOI: 10.1074/jbc.ra119.007681] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/05/2019] [Indexed: 11/06/2022] Open
Abstract
Adopting a proper topology is crucial for transmembrane proteins to perform their functions. We previously reported that ceramide regulates a transmembrane protein called TM4SF20 (transmembrane 4 L six family member 20) through topological inversion by altering the direction through which the protein is translocated across membranes during translation. This regulatory mechanism, denoted regulated alternative translocation (RAT), depends on a GXXXN motif present in the first transmembrane helix of TM4SF20. Here, using site-directed mutagenesis, we show that Asn-26 in the motif is crucial for RAT of TM4SF20, as it cannot be replaced even by Gln. In contrast, Gly-22 in the motif could be substituted by other small residues such as Ala and Ser without affecting RAT of TM4SF20. We further demonstrate that the GXXXN motif alone is insufficient to induce RAT of a transmembrane protein because TM4SF4, a relative of TM4SF20 that also contains the motif in the first transmembrane helix, did not undergo RAT. Using TM4SF40-TM4SF20 chimeras, we identified Pro-29 of TM4SF20 as another important element required for RAT of the protein. Substituting Pro-29 alone did not affect RAT of TM4SF20, whereas replacing Pro-29 together with either Leu-25 or Val-17 of TM4SF20 with the corresponding residues of TM4SF4 abolished RAT of TM4SF20. Because Val-17, Gly-22, Leu-25, Asn-26, and Pro-29 are predicted to reside along the same surface of the transmembrane helix, our results suggest that interactions with other proteins mediated by this surface during translocation may be critical for RAT of TM4SF20.
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Affiliation(s)
- Jingcheng Wang
- From the Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Lisa N Kinch
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Bray Denard
- From the Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Ching-En Lee
- From the Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | | | - Nick Grishin
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Jin Ye
- From the Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390.
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238
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Wang D, Eraslan B, Wieland T, Hallström B, Hopf T, Zolg DP, Zecha J, Asplund A, Li LH, Meng C, Frejno M, Schmidt T, Schnatbaum K, Wilhelm M, Ponten F, Uhlen M, Gagneur J, Hahne H, Kuster B. A deep proteome and transcriptome abundance atlas of 29 healthy human tissues. Mol Syst Biol 2019; 15:e8503. [PMID: 30777892 PMCID: PMC6379049 DOI: 10.15252/msb.20188503] [Citation(s) in RCA: 418] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 01/01/2019] [Accepted: 01/08/2019] [Indexed: 11/28/2022] Open
Abstract
Genome-, transcriptome- and proteome-wide measurements provide insights into how biological systems are regulated. However, fundamental aspects relating to which human proteins exist, where they are expressed and in which quantities are not fully understood. Therefore, we generated a quantitative proteome and transcriptome abundance atlas of 29 paired healthy human tissues from the Human Protein Atlas project representing human genes by 18,072 transcripts and 13,640 proteins including 37 without prior protein-level evidence. The analysis revealed that hundreds of proteins, particularly in testis, could not be detected even for highly expressed mRNAs, that few proteins show tissue-specific expression, that strong differences between mRNA and protein quantities within and across tissues exist and that protein expression is often more stable across tissues than that of transcripts. Only 238 of 9,848 amino acid variants found by exome sequencing could be confidently detected at the protein level showing that proteogenomics remains challenging, needs better computational methods and requires rigorous validation. Many uses of this resource can be envisaged including the study of gene/protein expression regulation and biomarker specificity evaluation.
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Affiliation(s)
- Dongxue Wang
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Basak Eraslan
- Computational Biology, Department of Informatics, Technical University of Munich, Garching bei München, Germany
- Department of Biochemistry, Quantitative Biosciences Munich, Gene Center, Ludwig Maximilian Universität, München, Germany
| | | | - Björn Hallström
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | | | - Daniel Paul Zolg
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Jana Zecha
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Anna Asplund
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Li-Hua Li
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Chen Meng
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Martin Frejno
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Tobias Schmidt
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | | | - Mathias Wilhelm
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Frederik Ponten
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Mathias Uhlen
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Julien Gagneur
- Computational Biology, Department of Informatics, Technical University of Munich, Garching bei München, Germany
| | | | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
- Center for Integrated Protein Science Munich (CIPSM), Munich, Germany
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239
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Anzalone AV, Zairis S, Lin AJ, Rabadan R, Cornish VW. Interrogation of Eukaryotic Stop Codon Readthrough Signals by in Vitro RNA Selection. Biochemistry 2019; 58:1167-1178. [PMID: 30698415 DOI: 10.1021/acs.biochem.8b01280] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
RNA signals located downstream of stop codons in eukaryotic mRNAs can stimulate high levels of translational readthrough by the ribosome, thereby giving rise to functionally distinct C-terminally extended protein products. Although many readthrough events have been previously discovered in Nature, a broader description of the stimulatory RNA signals would help to identify new reprogramming events in eukaryotic genes and provide insights into the molecular mechanisms of readthrough. Here, we explore the RNA reprogramming landscape by performing in vitro translation selections to enrich RNA readthrough signals de novo from a starting randomized library comprising >1013 unique sequence variants. Selection products were characterized using high-throughput sequencing, from which we identified primary sequence and secondary structure readthrough features. The activities of readthrough signals, including three novel sequence motifs, were confirmed in cellular reporter assays. Then, we used machine learning and our HTS data to predict readthrough activity from human 3'-untranslated region sequences. This led to the discovery of >1.5% readthrough in four human genes (CDKN2B, LEPROTL1, PVRL3, and SFTA2). Together, our results provide valuable insights into RNA-mediated translation reprogramming, offer tools for readthrough discovery in eukaryotic genes, and present new opportunities to explore the biological consequences of stop codon readthrough in humans.
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Affiliation(s)
- Andrew V Anzalone
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Sakellarios Zairis
- Department of Systems Biology , Columbia University , New York , New York 10032 , United States
| | - Annie J Lin
- Department of Chemistry , Columbia University , New York , New York 10027 , United States.,Department of Systems Biology , Columbia University , New York , New York 10032 , United States
| | - Raul Rabadan
- Department of Systems Biology , Columbia University , New York , New York 10032 , United States
| | - Virginia W Cornish
- Department of Chemistry , Columbia University , New York , New York 10027 , United States.,Department of Systems Biology , Columbia University , New York , New York 10032 , United States
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240
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Volloch V. Protein-Encoding RNA-to-RNA Information Transfer in Mammalian Cells: Principles of RNA-Dependent mRNA Amplification. ANNALS OF INTEGRATIVE MOLECULAR MEDICINE 2019; 1:1002. [PMID: 31535092 PMCID: PMC6750253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The transfer of protein-encoding genetic information from DNA to RNA to protein, a process formalized as the "Central Dogma of Molecular Biology", has undergone a significant evolution since its inception. It was amended to account for the information flow from RNA to DNA, the reverse transcription, and for the information transfer from RNA to RNA, the RNA-dependent RNA synthesis. These processes, both potentially leading to protein production, were initially described only in viral systems, and although RNA-dependent RNA polymerase activity was shown to be present, and RNA-dependent RNA synthesis found to occur, in mammalian cells, its function was presumed to be restricted to regulatory. However, recent results, obtained with multiple mRNA species in several mammalian systems, strongly indicate the occurrence of protein-encoding RNA to RNA information transfer in mammalian cells. It can result in the rapid production of the extraordinary quantities of specific proteins as was seen in cases of terminal cellular differentiation and during cellular deposition of extracellular matrix molecules. A malfunction of this process may be involved in pathologies associated either with the deficiency of a protein normally produced by this mechanism or with the abnormal abundance of a protein or of its C-terminal fragment. It seems to be responsible for some types of familial thalassemia and may underlie the overproduction of beta amyloid in sporadic Alzheimer's disease. The aim of the present article is to systematize the current knowledge and understanding of this pathway. The outlined framework introduces unexpected features of the mRNA amplification such as its ability to generate polypeptides non-contiguously encoded in the genome, its second Tier, a physiologically occurring intracellular polymerase chain reaction, iPCR, a "Two-Tier Paradox" and RNA "Dark Matter". RNA-dependent mRNA amplification represents a new mode of genomic protein-encoding information transfer in mammalian cells. Its potential physiological impact is substantial, it appears relevant to multiple pathologies and its understanding opens new venues of therapeutic interference, it suggests powerful novel bioengineering approaches and its further rigorous investigations are highly warranted.
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241
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Ruiz-Ruano FJ, Navarro-Domínguez B, Camacho JPM, Garrido-Ramos MA. Full plastome sequence of the fern Vandenboschia speciosa (Hymenophyllales): structural singularities and evolutionary insights. JOURNAL OF PLANT RESEARCH 2019; 132:3-17. [PMID: 30552526 DOI: 10.1007/s10265-018-1077-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/26/2018] [Indexed: 05/14/2023]
Abstract
We provide here the first full chloroplast genome sequence, i.e., the plastome, for a species belonging to the fern order Hymenophyllales. The phylogenetic position of this order within leptosporangiate ferns, together with the general scarcity of information about fern plastomes, places this research as a valuable study on the analysis of the diversity of plastomes throughout fern evolution. Gene content of V. speciosa plastome was similar to that in most ferns, although there were some characteristic gene losses and lineage-specific differences. In addition, an important number of genes required U to C RNA editing for proper protein translation and two genes showed start codons alternative to the canonical AUG (AUA). Concerning gene order, V. speciosa shared the specific 30-kb inversion of euphyllophytes plastomes and the 3.3-kb inversion of fern plastomes, keeping the ancestral gene order shared by eusporangiate and early leptosporangiate ferns. Conversely, V. speciosa has expanded IR regions comprising the rps7, rps12, ndhB and trnL genes in addition to rRNA and other tRNA genes, a condition shared with several eusporangiate ferns, lycophytes and hornworts, as well as most seed plants.
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Affiliation(s)
- F J Ruiz-Ruano
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - B Navarro-Domínguez
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - J P M Camacho
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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242
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Merrick WC, Pavitt GD. Protein Synthesis Initiation in Eukaryotic Cells. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a033092. [PMID: 29735639 DOI: 10.1101/cshperspect.a033092] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review summarizes our current understanding of the major pathway for the initiation phase of protein synthesis in eukaryotic cells, with a focus on recent advances. We describe the major scanning or messenger RNA (mRNA) m7G cap-dependent mechanism, which is a highly coordinated and stepwise regulated process that requires the combined action of at least 12 distinct translation factors with initiator transfer RNA (tRNA), ribosomes, and mRNAs. We limit our review to studies involving either mammalian or budding yeast cells and factors, as these represent the two best-studied experimental systems, and only include a reference to other organisms where particular insight has been gained. We close with a brief description of what we feel are some of the major unknowns in eukaryotic initiation.
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Affiliation(s)
- William C Merrick
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, United Kingdom
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243
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Jackson R, Kroehling L, Khitun A, Bailis W, Jarret A, York AG, Khan OM, Brewer JR, Skadow MH, Duizer C, Harman CCD, Chang L, Bielecki P, Solis AG, Steach HR, Slavoff S, Flavell RA. The translation of non-canonical open reading frames controls mucosal immunity. Nature 2018; 564:434-438. [PMID: 30542152 PMCID: PMC6939389 DOI: 10.1038/s41586-018-0794-7] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 10/17/2018] [Indexed: 11/09/2022]
Abstract
The annotation of the mammalian protein-coding genome is incomplete. Arbitrary size restriction of open reading frames (ORFs) and the absolute requirement for a methionine codon as the sole initiator of translation have constrained the identification of potentially important transcripts with non-canonical protein-coding potential1,2. Here, using unbiased transcriptomic approaches in macrophages that respond to bacterial infection, we show that ribosomes associate with a large number of RNAs that were previously annotated as 'non-protein coding'. Although the idea that such non-canonical ORFs can encode functional proteins is controversial3,4, we identify a range of short and non-ATG-initiated ORFs that can generate stable and spatially distinct proteins. Notably, we show that the translation of a new ORF 'hidden' within the long non-coding RNA Aw112010 is essential for the orchestration of mucosal immunity during both bacterial infection and colitis. This work expands our interpretation of the protein-coding genome and demonstrates that proteinaceous products generated from non-canonical ORFs are crucial for the immune response in vivo. We therefore propose that the misannotation of non-canonical ORF-containing genes as non-coding RNAs may obscure the essential role of a multitude of previously undiscovered protein-coding genes in immunity and disease.
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Affiliation(s)
- Ruaidhrí Jackson
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Lina Kroehling
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Will Bailis
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Abigail Jarret
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Autumn G York
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Omair M Khan
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - J Richard Brewer
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Mathias H Skadow
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Coco Duizer
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Christian C D Harman
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Lelina Chang
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Piotr Bielecki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Angel G Solis
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Holly R Steach
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Sarah Slavoff
- Department of Chemistry, Yale University, New Haven, CT, USA
- Chemical Biology Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.
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244
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Jankowsky E, Guenther UP. A helicase links upstream ORFs and RNA structure. Curr Genet 2018; 65:453-456. [PMID: 30483885 DOI: 10.1007/s00294-018-0911-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 01/08/2023]
Abstract
Upstream open reading frames (uORFs) in 5' UTRs of eukaryotic mRNAs are increasingly recognized as important elements that regulate cellular protein synthesis. Since uORFs can start from non-AUG codons, an enormous number of potential uORF initiation sites exists in 5'UTRs. However, only a subset of these sites is used and it has been unclear how actual start sites are selected. Studies of the DEAD-box helicase Ded1p from S. cerevisiae show that translation of uORFs with non-AUG initiation codons occurs upstream of mRNA structures that emerge with defective Ded1p. The data designate mRNA structure as important determinant for non-AUG initiation sites of uORFs. Ded1p can control this RNA structure and thereby regulate uORF translation.
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Affiliation(s)
- Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.
| | - Ulf-Peter Guenther
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,EMBL, Heidelberg, Germany
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245
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Sriram A, Bohlen J, Teleman AA. Translation acrobatics: how cancer cells exploit alternate modes of translational initiation. EMBO Rep 2018; 19:embr.201845947. [PMID: 30224410 DOI: 10.15252/embr.201845947] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 07/09/2018] [Accepted: 08/16/2018] [Indexed: 12/11/2022] Open
Abstract
Recent work has brought to light many different mechanisms of translation initiation that function in cells in parallel to canonical cap-dependent initiation. This has important implications for cancer. Canonical cap-dependent translation initiation is inhibited by many stresses such as hypoxia, nutrient limitation, proteotoxic stress, or genotoxic stress. Since cancer cells are often exposed to these stresses, they rely on alternate modes of translation initiation for protein synthesis and cell growth. Cancer mutations are now being identified in components of the translation machinery and in cis-regulatory elements of mRNAs, which both control translation of cancer-relevant genes. In this review, we provide an overview on the various modes of non-canonical translation initiation, such as leaky scanning, translation re-initiation, ribosome shunting, IRES-dependent translation, and m6A-dependent translation, and then discuss the influence of stress on these different modes of translation. Finally, we present examples of how these modes of translation are dysregulated in cancer cells, allowing them to grow, to proliferate, and to survive, thereby highlighting the importance of translational control in cancer.
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Affiliation(s)
- Ashwin Sriram
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Jonathan Bohlen
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ), Heidelberg, Germany .,Heidelberg University, Heidelberg, Germany
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246
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Crawford RA, Pavitt GD. Translational regulation in response to stress in Saccharomyces cerevisiae. Yeast 2018; 36:5-21. [PMID: 30019452 PMCID: PMC6492140 DOI: 10.1002/yea.3349] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/08/2018] [Accepted: 06/25/2018] [Indexed: 12/19/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae must dynamically alter the composition of its proteome in order to respond to diverse stresses. The reprogramming of gene expression during stress typically involves initial global repression of protein synthesis, accompanied by the activation of stress‐responsive mRNAs through both translational and transcriptional responses. The ability of specific mRNAs to counter the global translational repression is therefore crucial to the overall response to stress. Here we summarize the major repressive mechanisms and discuss mechanisms of translational activation in response to different stresses in S. cerevisiae. Taken together, a wide range of studies indicate that multiple elements act in concert to bring about appropriate translational responses. These include regulatory elements within mRNAs, altered mRNA interactions with RNA‐binding proteins and the specialization of ribosomes that each contribute towards regulating protein expression to suit the changing environmental conditions.
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Affiliation(s)
- Robert A Crawford
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Michael Smith Building, Dover Street, Manchester, M13 9PT, UK
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Michael Smith Building, Dover Street, Manchester, M13 9PT, UK
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247
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Nishizawa T, Sugimoto Y, Takeda T, Kodera Y, Hatano Y, Takahashi M, Okamoto H. Identification and whole genome characterization of novel anelloviruses in masked palm civets (Paguma larvata): Segregation into four distinct clades. Virus Res 2018; 256:183-191. [PMID: 30149046 DOI: 10.1016/j.virusres.2018.08.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/16/2018] [Accepted: 08/20/2018] [Indexed: 10/28/2022]
Abstract
The members of the family Anelloviridae are small and single-stranded DNA viruses with marked diversity in sequence and length, which ubiquitously infect many vertebrates, including mammals, birds and reptiles. The anelloviruses isolated from mammals are currently classified into 11 assigned and four proposed genera; some anelloviruses remain unassigned. The present study was conducted to identify anelloviruses in wild-caught masked palm civets (Paguma larvata) in Japan using a rolling-circle amplification method. Thirteen novel anellovirus strains were identified from 8 of 10 masked palm civets and their entire genomic sequences (2039-2535 nucleotides) were determined; they were classifiable into four distinct clades. Comparative analyses of all reported anelloviruses for which the entire or near-entire genomic sequences have been determined, including the 13 strains obtained in the present study, revealed that anelloviruses can provisionally be classified into 20 clades, which may correspond to 20 genera (including 11 assigned and four proposed genera) by a >70% amino acid sequence difference in open reading frame 1 (ORF1). This study suggested that novel anelloviruses of marked diversity are circulating in animals worldwide, and that the rolling-circle amplification method would be useful for identifying novel anelloviruses and other viruses with a circular DNA genome.
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Affiliation(s)
- Tsutomu Nishizawa
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, 329-0498, Japan
| | - Yuji Sugimoto
- Nikko Branch, Tochigi Hunter Association, Nikko, Tochigi, 321-2522, Japan
| | - Tsutomu Takeda
- Center for Weeds and Wildlife Management, Utsunomiya University, Utsunomiya, Tochigi, 321-8505, Japan
| | - Yuuji Kodera
- Center for Weeds and Wildlife Management, Utsunomiya University, Utsunomiya, Tochigi, 321-8505, Japan
| | - Yumi Hatano
- Sakakibara Heart Institute Clinic, Shinjuku-ku, Tokyo, 163-0804, Japan
| | - Masaharu Takahashi
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, 329-0498, Japan
| | - Hiroaki Okamoto
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, 329-0498, Japan.
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248
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Sonobe Y, Ghadge G, Masaki K, Sendoel A, Fuchs E, Roos RP. Translation of dipeptide repeat proteins from the C9ORF72 expanded repeat is associated with cellular stress. Neurobiol Dis 2018; 116:155-165. [PMID: 29792928 DOI: 10.1016/j.nbd.2018.05.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 01/13/2023] Open
Abstract
Expansion of a hexanucleotide repeat (HRE), GGGGCC, in the C9ORF72 gene is recognized as the most common cause of familial amyotrophic lateral sclerosis (FALS), frontotemporal dementia (FTD) and ALS-FTD, as well as 5-10% of sporadic ALS. Despite the location of the HRE in the non-coding region (with respect to the main C9ORF72 gene product), dipeptide repeat proteins (DPRs) that are thought to be toxic are translated from the HRE in all three reading frames from both the sense and antisense transcript. Here, we identified a CUG that has a good Kozak consensus sequence as the translation initiation codon. Mutation of this CTG significantly suppressed polyglycine-alanine (GA) translation. GA was translated when the G4C2 construct was placed as the second cistron in a bicistronic construct. CRISPR/Cas9-induced knockout of a non-canonical translation initiation factor, eIF2A, impaired GA translation. Transfection of G4C2 constructs induced an integrated stress response (ISR), while triggering the ISR led to a continuation of translation of GA with a decline in conventional cap-dependent translation. These in vitro observations were confirmed in chick embryo neural cells. The findings suggest that DPRs translated from an HRE in C9ORF72 aggregate and lead to an ISR that then leads to continuing DPR production and aggregation, thereby creating a continuing pathogenic cycle.
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Affiliation(s)
- Yoshifumi Sonobe
- Department of Neurology, University of Chicago Medical Center, 5841 S. Maryland Ave., Chicago, IL 60637, United States
| | - Ghanashyam Ghadge
- Department of Neurology, University of Chicago Medical Center, 5841 S. Maryland Ave., Chicago, IL 60637, United States
| | - Katsuhisa Masaki
- Department of Neurology, University of Chicago Medical Center, 5841 S. Maryland Ave., Chicago, IL 60637, United States
| | - Ataman Sendoel
- Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, 1230 York Ave., Box 300, NY, NY, 10021-6399, United States
| | - Elaine Fuchs
- Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, 1230 York Ave., Box 300, NY, NY, 10021-6399, United States
| | - Raymond P Roos
- Department of Neurology, University of Chicago Medical Center, 5841 S. Maryland Ave., Chicago, IL 60637, United States.
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249
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Shirokikh NE, Preiss T. Translation initiation by cap-dependent ribosome recruitment: Recent insights and open questions. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1473. [PMID: 29624880 DOI: 10.1002/wrna.1473] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/02/2018] [Accepted: 02/14/2018] [Indexed: 12/14/2022]
Abstract
Gene expression universally relies on protein synthesis, where ribosomes recognize and decode the messenger RNA template by cycling through translation initiation, elongation, and termination phases. All aspects of translation have been studied for decades using the tools of biochemistry and molecular biology available at the time. Here, we focus on the mechanism of translation initiation in eukaryotes, which is remarkably more complex than prokaryotic initiation and is the target of multiple types of regulatory intervention. The "consensus" model, featuring cap-dependent ribosome entry and scanning of mRNA leader sequences, represents the predominantly utilized initiation pathway across eukaryotes, although several variations of the model and alternative initiation mechanisms are also known. Recent advances in structural biology techniques have enabled remarkable molecular-level insights into the functional states of eukaryotic ribosomes, including a range of ribosomal complexes with different combinations of translation initiation factors that are thought to represent bona fide intermediates of the initiation process. Similarly, high-throughput sequencing-based ribosome profiling or "footprinting" approaches have allowed much progress in understanding the elongation phase of translation, and variants of them are beginning to reveal the remaining mysteries of initiation, as well as aspects of translation termination and ribosomal recycling. A current view on the eukaryotic initiation mechanism is presented here with an emphasis on how recent structural and footprinting results underpin axioms of the consensus model. Along the way, we further outline some contested mechanistic issues and major open questions still to be addressed. This article is categorized under: Translation > Translation Mechanisms Translation > Translation Regulation RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
- Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
- Victor Chang Cardiac Research Institute, Darlinghurst, Australia
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250
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Pagnamenta AT, Murakami Y, Anzilotti C, Titheradge H, Oates AJ, Morton J, Kinoshita T, Kini U, Taylor JC. A homozygous variant disrupting the PIGH start-codon is associated with developmental delay, epilepsy, and microcephaly. Hum Mutat 2018; 39:822-826. [PMID: 29573052 PMCID: PMC6001798 DOI: 10.1002/humu.23420] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/09/2018] [Accepted: 03/02/2018] [Indexed: 01/12/2023]
Abstract
Defective glycosylphosphatidylinositol (GPI)‐anchor biogenesis can cause a spectrum of predominantly neurological problems. For eight genes critical to this biological process, disease associations are not yet reported. Scanning exomes from 7,833 parent–child trios and 1,792 singletons from the DDD study for biallelic variants in this gene‐set uncovered a rare PIGH variant in a boy with epilepsy, microcephaly, and behavioral difficulties. Although only 2/2 reads harbored this c.1A > T transversion, the presence of ∼25 Mb autozygosity at this locus implied homozygosity, which was confirmed using Sanger sequencing. A similarly‐affected sister was also homozygous. FACS analysis of PIGH‐deficient CHO cells indicated that cDNAs with c.1A > T could not efficiently restore expression of GPI‐APs. Truncation of PIGH protein was consistent with the utilization of an in‐frame start‐site at codon 63. In summary, we describe siblings harboring a homozygous c.1A > T variant resulting in defective GPI‐anchor biogenesis and highlight the importance of exploring low‐coverage variants within autozygous regions.
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Affiliation(s)
- Alistair T Pagnamenta
- National Institute for Health Research Oxford Biomedical Research Centre, Wellcome Centre for Human Genetics, University of Oxford, Oxford, Oxfordshire, UK
| | - Yoshiko Murakami
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Consuelo Anzilotti
- Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Hannah Titheradge
- West Midlands Regional Clinical Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's NHS Foundation Trust, Birmingham Women's Hospital, Mindelsohn Way, Edgbaston, Birmingham, UK
| | - Adam J Oates
- Radiology Department, Birmingham Children's Hospital, Birmingham, UK
| | - Jenny Morton
- West Midlands Regional Clinical Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's NHS Foundation Trust, Birmingham Women's Hospital, Mindelsohn Way, Edgbaston, Birmingham, UK
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- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Taroh Kinoshita
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Usha Kini
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Jenny C Taylor
- National Institute for Health Research Oxford Biomedical Research Centre, Wellcome Centre for Human Genetics, University of Oxford, Oxford, Oxfordshire, UK
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