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Bookey N, Drago P, Leung KY, Hughes L, MacCooey A, Ozaki M, Henry M, De Castro SCP, Doykov I, Heywood WE, Mills K, Murphy MM, Cavallé-Busquets P, Campbell S, Burtenshaw D, Meleady P, Cahill PA, Greene NDE, Parle-McDermott A. The Differential Translation Capabilities of the Human DHFR2 Gene Indicates a Developmental and Tissue-Specific Endogenous Protein of Low Abundance. Mol Cell Proteomics 2024; 23:100718. [PMID: 38224738 PMCID: PMC10884974 DOI: 10.1016/j.mcpro.2024.100718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/05/2024] [Accepted: 01/12/2024] [Indexed: 01/17/2024] Open
Abstract
A functional role has been ascribed to the human dihydrofolate reductase 2 (DHFR2) gene based on the enzymatic activity of recombinant versions of the predicted translated protein. However, the in vivo function is still unclear. The high amino acid sequence identity (92%) between DHFR2 and its parental homolog, DHFR, makes analysis of the endogenous protein challenging. This paper describes a targeted mass spectrometry proteomics approach in several human cell lines and tissue types to identify DHFR2-specific peptides as evidence of its translation. We show definitive evidence that the DHFR2 activity in the mitochondria is in fact mediated by DHFR, and not DHFR2. Analysis of Ribo-seq data and an experimental assessment of ribosome association using a sucrose cushion showed that the two main Ensembl annotated mRNA isoforms of DHFR2, 201 and 202, are differentially associated with the ribosome. This indicates a functional role at both the RNA and protein level. However, we were unable to detect DHFR2 protein at a detectable level in most cell types examined despite various RNA isoforms of DHFR2 being relatively abundant. We did detect a DHFR2-specific peptide in embryonic heart, indicating that the protein may have a specific role during embryogenesis. We propose that the main functionality of the DHFR2 gene in adult cells is likely to arise at the RNA level.
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Affiliation(s)
- Niamh Bookey
- School of Biotechnology, Dublin City University, Dublin, Ireland; DCU Life Sciences Institute, Dublin City University, Dublin, Ireland.
| | - Paola Drago
- School of Biotechnology, Dublin City University, Dublin, Ireland; DCU Life Sciences Institute, Dublin City University, Dublin, Ireland
| | - Kit-Yi Leung
- Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Linda Hughes
- School of Biotechnology, Dublin City University, Dublin, Ireland
| | - Aoife MacCooey
- School of Biotechnology, Dublin City University, Dublin, Ireland
| | - Mari Ozaki
- School of Biotechnology, Dublin City University, Dublin, Ireland
| | - Michael Henry
- DCU Life Sciences Institute, Dublin City University, Dublin, Ireland
| | - Sandra C P De Castro
- Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Ivan Doykov
- Translational Mass Spectrometry Research Group, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Wendy E Heywood
- Translational Mass Spectrometry Research Group, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Kevin Mills
- Translational Mass Spectrometry Research Group, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Michelle M Murphy
- Area of Preventive Medicine and Public Health, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, IISPV and CIBERobn (Instituto de Salud Carlos III), Reus, Spain
| | - Pere Cavallé-Busquets
- Area of Obstetrics, Hospital Universitari Sant Joan de Reus, IISPV and CIBERobn (Instituto de Salud Carlos III), Reus, Spain
| | - Susan Campbell
- Sheffield Hallam University, Department of Biosciences and Chemistry, Sheffield, UK
| | | | - Paula Meleady
- School of Biotechnology, Dublin City University, Dublin, Ireland; DCU Life Sciences Institute, Dublin City University, Dublin, Ireland
| | - Paul A Cahill
- School of Biotechnology, Dublin City University, Dublin, Ireland
| | - Nicholas D E Greene
- Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Anne Parle-McDermott
- School of Biotechnology, Dublin City University, Dublin, Ireland; DCU Life Sciences Institute, Dublin City University, Dublin, Ireland.
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Wolujewicz P, Steele JW, Kaltschmidt JA, Finnell RH, Ross ME. Unraveling the complex genetics of neural tube defects: From biological models to human genomics and back. Genesis 2021; 59:e23459. [PMID: 34713546 DOI: 10.1002/dvg.23459] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/08/2021] [Accepted: 09/17/2021] [Indexed: 12/11/2022]
Abstract
Neural tube defects (NTDs) are a classic example of preventable birth defects for which there is a proven-effective intervention, folic acid (FA); however, further methods of prevention remain unrealized. In the decades following implementation of FA nutritional fortification programs throughout at least 87 nations, it has become apparent that not all NTDs can be prevented by FA. In the United States, FA fortification only reduced NTD rates by 28-35% (Williams et al., 2015). As such, it is imperative that further work is performed to understand the risk factors associated with NTDs and their underlying mechanisms so that alternative prevention strategies can be developed. However, this is complicated by the sheer number of genes associated with neural tube development, the heterogeneity of observable phenotypes in human cases, the rareness of the disease, and the myriad of environmental factors associated with NTD risk. Given the complex genetic architecture underlying NTD pathology and the way in which that architecture interacts dynamically with environmental factors, further prevention initiatives will undoubtedly require precision medicine strategies that utilize the power of human genomics and modern tools for assessing genetic risk factors. Herein, we review recent advances in genomic strategies for discovering genetic variants associated with these defects, and new ways in which biological models, such as mice and cell culture-derived organoids, are leveraged to assess mechanistic functionality, the way these variants interact with other genetic or environmental factors, and their ultimate contribution to human NTD risk.
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Affiliation(s)
- Paul Wolujewicz
- Center for Neurogenetics, Feil Family Brain & Mind Research Institute, Weill Cornell Medicine, New York, New York, USA
| | - John W Steele
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Julia A Kaltschmidt
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA
| | - Richard H Finnell
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Margaret Elizabeth Ross
- Center for Neurogenetics, Feil Family Brain & Mind Research Institute, Weill Cornell Medicine, New York, New York, USA
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