Revisiting the pathogenic mechanism of the GJB1 5’ UTR c.-103C > T mutation causing CMTX1
Autor: | Bianca R. Grosz, Marina L. Kennerson, Gonzalo Perez-Siles, John Svaren, Garth A. Nicholson |
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Rok vydání: | 2021 |
Předmět: |
0301 basic medicine
Untranslated region Charcot-Marie-Tooth Five prime untranslated region Cap-independent translation medicine.disease_cause Connexins Nucleic acid secondary structure 03 medical and health sciences Cellular and Molecular Neuroscience 0302 clinical medicine Charcot-Marie-Tooth Disease Genes X-Linked IRES Genetics medicine Animals CMTX1 Gene Genetics (clinical) Mutation Chemistry Intron Gap Junctions Ribosomal RNA Molecular biology Rats Neuropathy Internal ribosome entry site 030104 developmental biology Original Article 5' Untranslated Regions 030217 neurology & neurosurgery |
Zdroj: | Neurogenetics |
ISSN: | 1364-6753 1364-6745 |
Popis: | The second most common form of Charcot-Marie-Tooth neuropathy (CMT), X-linked CMT type X1 (CMTX1), is caused by coding and non-coding mutations in the gap junction beta 1 (GJB1) gene. The non-coding GJB1 c.-103C > T mutation (NM_000166.5) has been reported to cause CMTX1 in multiple families. This study assessed the internal ribosomal entry site (IRES) activity previously reported for the rat Gjb1 P2 5’ untranslated region (UTR). Using a bicistronic assay and transfecting RT4 Schwann cells, IRES activity of the human GJB1 P2 5’ UTR was compared to the GJB1 P2 5’ UTR containing either the c.-103C > T mutation or the non-pathogenic c.-102G > A variant. No differences in GJB1 P2 5’ UTR IRES activity were observed between the negative control, the wild-type P2 5’ UTR, the c.-103C > T 5’ UTR or the c.-102G > A 5’ UTR, irrespective of the GJB1 intron being present (p = .429 with intron, and p = .865 without). A theoretical c.-131A > G variant was predicted to result in the same RNA secondary structure as the GJB1 c.-103C > T P2 5’ UTR. However, no significant difference was observed between expression from the wild-type GJB1 P2 5’ UTR and the GJB1 c.-131A > G variant (p = .688). Deletion of the conserved region surrounding the c.-103C > T mutation (c.-108_-103del) resulted in significantly higher expression than the c.-103C > T mutation alone (p = .019), suggesting that the conserved c.-108_-103 region was not essential for translation. The reporter assays in this study do not recapitulate the previously reported GJB1 IRES activity and suggest an alternate pathogenic mechanism for the c.-103C > T CMTX1 non-coding mutation. |
Databáze: | OpenAIRE |
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