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Roos D, de Boer M. Mutations in cis that affect mRNA synthesis, processing and translation. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166166. [PMID: 33971252 DOI: 10.1016/j.bbadis.2021.166166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/17/2022]
Abstract
Genetic mutations that cause hereditary diseases usually affect the composition of the transcribed mRNA and its encoded protein, leading to instability of the mRNA and/or the protein. Sometimes, however, such mutations affect the synthesis, the processing or the translation of the mRNA, with similar disastrous effects. We here present an overview of mRNA synthesis, its posttranscriptional modification and its translation into protein. We then indicate which elements in these processes are known to be affected by pathogenic mutations, but we restrict our review to mutations in cis, in the DNA of the gene that encodes the affected protein. These mutations can be in enhancer or promoter regions of the gene, which act as binding sites for transcription factors involved in pre-mRNA synthesis. We also describe mutations in polyadenylation sequences and in splice site regions, exonic and intronic, involved in intron removal. Finally, we include mutations in the Kozak sequence in mRNA, which is involved in protein synthesis. We provide examples of genetic diseases caused by mutations in these DNA regions and refer to databases to help identify these regions. The over-all knowledge of mRNA synthesis, processing and translation is essential for improvement of the diagnosis of patients with genetic diseases.
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Affiliation(s)
- Dirk Roos
- Sanquin Blood Supply Organization, Dept. of Blood Cell Research, Landsteiner Laboratory, Amsterdam University Medical Centre, location AMC, University of Amsterdam, Amsterdam, the Netherlands.
| | - Martin de Boer
- Sanquin Blood Supply Organization, Dept. of Blood Cell Research, Landsteiner Laboratory, Amsterdam University Medical Centre, location AMC, University of Amsterdam, Amsterdam, the Netherlands
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Markunas AM, Manivannan PKR, Ezekian JE, Agarwal A, Eisner W, Alsina K, Allen HD, Wray GA, Kim JJ, Wehrens XHT, Landstrom AP. TBX5-encoded T-box transcription factor 5 variant T223M is associated with long QT syndrome and pediatric sudden cardiac death. Am J Med Genet A 2020; 185:923-929. [PMID: 33369127 DOI: 10.1002/ajmg.a.62037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022]
Abstract
Long QT syndrome (LQTS) is a genetic disease resulting in a prolonged QT interval on a resting electrocardiogram, predisposing affected individuals to polymorphic ventricular tachycardia and sudden death. Although a number of genes have been implicated in this disease, nearly one in four individuals exhibiting the LQTS phenotype are genotype-negative. Whole-exome sequencing identified a missense T223M variant in TBX5 that cosegregates with prolonged QT interval in a family with otherwise genotype-negative LQTS and sudden death. The TBX5-T223M variant was absent among large ostensibly healthy populations (gnomAD) and predicted to be pathogenic by in silico modeling based on Panther, PolyPhen-2, Provean, SIFT, SNAP2, and PredictSNP prediction tools. The variant was located in a highly conserved region of TBX5 predicted to be part of the DNA-binding interface. A luciferase assay identified a 57.5% reduction in the ability of TBX5-T223M to drive expression at the atrial natriuretic factor promotor compared to wildtype TBX5 in vitro. We conclude that the variant is pathogenic in this family, and we put TBX5 forward as a disease susceptibility allele for genotype-negative LQTS. The identification of this familial variant may serve as a basis for the identification of previously unknown mechanisms of LQTS with broader implications for cardiac electrophysiology.
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Affiliation(s)
- Alexandra M Markunas
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Perathu K R Manivannan
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Jordan E Ezekian
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Agnim Agarwal
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - William Eisner
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Katherina Alsina
- Departments of Molecular Physiology & Biophysics and Medicine (Cardiology), Baylor College of Medicine, Houston, Texas, USA
| | - Hugh D Allen
- Department of Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, Texas, USA
| | - Gregory A Wray
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Jeffrey J Kim
- Department of Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, Texas, USA
| | - Xander H T Wehrens
- Departments of Molecular Physiology & Biophysics and Medicine (Cardiology), Baylor College of Medicine, Houston, Texas, USA
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA.,Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
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