m6A modification of mutant huntingtin RNA promotes the biogenesis of pathogenic huntingtin transcripts
In Huntington's disease (HD), aberrant processing of huntingtin (HTT) mRNA produces HTT1a transcripts that encode the pathogenic HTT exon 1 protein. The mechanisms behind HTT1a production are not fully understood. Considering the role of m<sup>6</sup>A in RNA processing and splicing, we investigated its involvement in HTT1a generation. Here, we show that m<sup>6</sup>A methylation is increased before the cryptic poly(A) sites (IpA1 and IpA2) within the huntingtin RNA in the striatum of Hdh+/Q111 mice and human HD samples. We further assessed m<sup>6</sup>A's role in mutant Htt mRNA processing by pharmacological inhibition and knockdown of METTL3, as well as targeted demethylation of Htt intron 1 using a dCas13-ALKBH5 system in HD mouse cells. Our data reveal that Htt1a transcript levels are regulated by both METTL3 and the methylation status of Htt intron 1. They also show that m<sup>6</sup>A methylation in intron 1 depends on expanded CAG repeats. Our findings highlight a potential role for m<sup>6</sup>A in aberrant splicing of Htt mRNA.
Authors
- Daniel del Toro (ORCID: https://orcid.org/0000-0002-7416-2155)
- Gillian P. Bates (ORCID: https://orcid.org/0000-0002-4041-6305)
- Anika Pupak (ORCID: https://orcid.org/0000-0003-2653-9189)
- Eulàlia Martı́ (ORCID: https://orcid.org/0000-0002-1030-3158)
- Kirupa Sathasivam
- Sílvia Ginés (ORCID: https://orcid.org/0000-0002-9479-8185)
- Ricardo Mouro Pinto (ORCID: https://orcid.org/0000-0001-6744-2805)
- Ulf Andersson Ørom (ORCID: https://orcid.org/0000-0002-0643-0592)
- Verónica Brito (ORCID: https://orcid.org/0000-0002-4137-0708)
- Irene Rodríguez-Navarro (ORCID: https://orcid.org/0000-0002-1863-2124)
- Amelie Essmann (ORCID: https://orcid.org/0009-0008-9972-8187)
- Ankita Singh (ORCID: https://orcid.org/0000-0001-8339-3337)
Institutions
- Broad Institute (US)
- Harvard University (US)
- Aarhus University (DK)
- Biomedical Research Networking Center on Neurodegenerative Diseases (ES)
- Massachusetts General Hospital (US)
- UK Dementia Research Institute (GB)
- Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (ES)
- Consorci Institut D'Investigacions Biomediques August Pi I Sunyer (ES)
- University College London (GB)
- Universitat de Barcelona (ES)
Publication Details
- Journal
- EMBO Reports
- Published
- 2024-10-11
- DOI
- https://doi.org/10.1038/s44319-024-00283-7
- Citations
- 6
- Primary Topic
- RNA modifications and cancer
- Type
- article
- Field-Weighted Citation Impact
- 1.40
Funders
- Hereditary Disease Foundation
- Ministerio de Ciencia, Innovación y Universidades
- Generalitat de Catalunya
- Ministerio de Ciencia e Innovación
- Universitat de Barcelona
- National Institutes of Health