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Lookup NU author(s): Dr Kyle Thompson, Dr Charlotte Alston, Dr Langping He, Dr Angela Pyle, Dr Helen GriffinORCiD, Professor Patrick Chinnery, Professor Bobby McFarlandORCiD, Professor Robert Taylor
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Mitochondrial disorders are clinically and genetically diverse, with mutations in mitochondrial or nuclear genes able to cause defects in mitochondrial gene expression. Recently, mutations in several genes encoding factors involved in mt-tRNA processing have been identified to cause mitochondrial disease. Using whole-exome sequencing, we identified mutations in TRMT10C (encoding the mitochondrial RNase P protein 1 [MRPP1]) in two unrelated individuals who presented at birth with lactic acidosis, hypotonia, feeding difficulties, and deafness. Both individuals died at 5 months after respiratory failure. MRPP1, along with MRPP2 and MRPP3, form the mitochondrial ribonuclease P (mt-RNase P) complex that cleaves the 50 ends of mt-tRNAs from polycistronic precursor transcripts. Additionally, a stable complex of MRPP1 and MRPP2 has m(1)R9 methyltransferase activity, which methylates mt-tRNAs at position 9 and is vital for folding mt-tRNAs into their correct tertiary structures. Analyses of fibroblasts from affected individuals harboring TRMT10C missense variants revealed decreased protein levels of MRPP1 and an increase in mt-RNA precursors indicative of impaired mt-RNA processing and defective mitochondrial protein synthesis. The pathogenicity of the detected variants-compound heterozygous c.542G>T (p.Arg181Leu) and c.814A>G (p.Thr272Ala) changes in subject 1 and a homozygous c.542G>T (p.Arg181Leu) variant in subject 2-was validated by the functional rescue of mt-RNA processing and mitochondrial protein synthesis defects after lentiviral transduction of wild-type TRMT10C. Our study suggests that these variants affect MRPP1 protein stability and mt-tRNA processing without affecting m(1)R9 methyltransferase activity, identifying mutations in TRMT10C as a cause of mitochondrial disease and highlighting the importance of RNA processing for correct mitochondrial function.
Author(s): Metodiev MD, Thompson K, Alston CL, Morris AAM, He LP, Assouline Z, Rio M, Bahi-Buisson N, Pyle A, Griffin H, Siira S, Filipovska A, Munnich A, Chinnery PF, McFarland R, Rotig A, Taylor RW
Publication type: Article
Publication status: Published
Journal: American Journal of Human Genetics
Year: 2016
Volume: 98
Issue: 5
Pages: 993-1000
Print publication date: 05/05/2016
Online publication date: 28/04/2016
Acceptance date: 14/03/2016
Date deposited: 05/07/2016
ISSN (print): 0002-9297
ISSN (electronic): 1537-6605
Publisher: Cell Press
URL: http://dx.doi.org/10.1016/j.ajhg.2016.03.010
DOI: 10.1016/j.ajhg.2016.03.010
PubMed id: 27132592
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