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(CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage
Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disorder caused by the expression of trinucleotide repeat-containing DMPK transcripts. Abnormally expanded (CUG)n repeats in these transcripts form hairpin-like structures that cause the RNA to accumulate in the cell nucleus by sequestering i...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6530876/ https://www.ncbi.nlm.nih.gov/pubmed/31116797 http://dx.doi.org/10.1371/journal.pone.0217317 |
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author | André, Laurène M. van Cruchten, Remco T. P. Willemse, Marieke Wansink, Derick G. |
author_facet | André, Laurène M. van Cruchten, Remco T. P. Willemse, Marieke Wansink, Derick G. |
author_sort | André, Laurène M. |
collection | PubMed |
description | Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disorder caused by the expression of trinucleotide repeat-containing DMPK transcripts. Abnormally expanded (CUG)n repeats in these transcripts form hairpin-like structures that cause the RNA to accumulate in the cell nucleus by sequestering isoforms of the Muscleblind (MBNL) family, tissue-specific regulators of developmentally programmed, post-transcriptional processes in RNA metabolism. Through this mechanism, the function of MBNL in RNA processing becomes dominantly perturbed, which eventually leads to aberrant alternative splicing and the expression of foetal splice variants of a wide variety of proteins, including the MBNL isoforms themselves. Here, we employ a patient-derived muscle cell model for DM1 to examine in detail the expression of MBNL RNA and protein variants during myogenic differentiation. This DM1 model consists of a panel of isogenic myoblast cell lines that either contain a pathogenic DMPK allele with a congenital mutation of 2600 triplets, or lack this expanded repeat through CRISPR/Cas9-mediated gene editing. We found that the temporal expression levels of MBNL1, MBNL2 and MBNL3 RNAs are not influenced by presence of the (CTG)2600 repeat during myogenesis in vitro. However, throughout myoblast proliferation and differentiation to myotubes a disproportionate inclusion of MBNL1 exon 5 and MBNL2 exons 5 and 8 occurs in cells with the (CTG)2600 repeat. As a consequence, a reduced quantity and imbalanced collection of splice variants of MBNL1 and MBNL2 accumulates in both the cytoplasm and the nucleus of DM1 myoblasts and myotubes. We thus propose that both the quantitative and qualitative changes in the intracellular partitioning of MBNL proteins are a pivotal cause of skeletal muscle problems in DM1, starting already in muscle progenitor cells. |
format | Online Article Text |
id | pubmed-6530876 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-65308762019-05-31 (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage André, Laurène M. van Cruchten, Remco T. P. Willemse, Marieke Wansink, Derick G. PLoS One Research Article Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disorder caused by the expression of trinucleotide repeat-containing DMPK transcripts. Abnormally expanded (CUG)n repeats in these transcripts form hairpin-like structures that cause the RNA to accumulate in the cell nucleus by sequestering isoforms of the Muscleblind (MBNL) family, tissue-specific regulators of developmentally programmed, post-transcriptional processes in RNA metabolism. Through this mechanism, the function of MBNL in RNA processing becomes dominantly perturbed, which eventually leads to aberrant alternative splicing and the expression of foetal splice variants of a wide variety of proteins, including the MBNL isoforms themselves. Here, we employ a patient-derived muscle cell model for DM1 to examine in detail the expression of MBNL RNA and protein variants during myogenic differentiation. This DM1 model consists of a panel of isogenic myoblast cell lines that either contain a pathogenic DMPK allele with a congenital mutation of 2600 triplets, or lack this expanded repeat through CRISPR/Cas9-mediated gene editing. We found that the temporal expression levels of MBNL1, MBNL2 and MBNL3 RNAs are not influenced by presence of the (CTG)2600 repeat during myogenesis in vitro. However, throughout myoblast proliferation and differentiation to myotubes a disproportionate inclusion of MBNL1 exon 5 and MBNL2 exons 5 and 8 occurs in cells with the (CTG)2600 repeat. As a consequence, a reduced quantity and imbalanced collection of splice variants of MBNL1 and MBNL2 accumulates in both the cytoplasm and the nucleus of DM1 myoblasts and myotubes. We thus propose that both the quantitative and qualitative changes in the intracellular partitioning of MBNL proteins are a pivotal cause of skeletal muscle problems in DM1, starting already in muscle progenitor cells. Public Library of Science 2019-05-22 /pmc/articles/PMC6530876/ /pubmed/31116797 http://dx.doi.org/10.1371/journal.pone.0217317 Text en © 2019 André et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article André, Laurène M. van Cruchten, Remco T. P. Willemse, Marieke Wansink, Derick G. (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage |
title | (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage |
title_full | (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage |
title_fullStr | (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage |
title_full_unstemmed | (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage |
title_short | (CTG)n repeat-mediated dysregulation of MBNL1 and MBNL2 expression during myogenesis in DM1 occurs already at the myoblast stage |
title_sort | (ctg)n repeat-mediated dysregulation of mbnl1 and mbnl2 expression during myogenesis in dm1 occurs already at the myoblast stage |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6530876/ https://www.ncbi.nlm.nih.gov/pubmed/31116797 http://dx.doi.org/10.1371/journal.pone.0217317 |
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