{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T10:02:47Z","timestamp":1789984967284,"version":"4.0.1"},"reference-count":55,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T00:00:00Z","timestamp":1789776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["R21NS119952"],"award-info":[{"award-number":["R21NS119952"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["R21NS112766"],"award-info":[{"award-number":["R21NS112766"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["R21AG085076"],"award-info":[{"award-number":["R21AG085076"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>A hexanucleotide repeat expansion in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Bidirectional transcription of the repeat expansion generates sense and antisense RNAs that are translated into dipeptide repeat (DPR) proteins, but the mechanisms of translation initiation remain incompletely understood. Here, we used CRISPR-Cas9 genome editing and steric-blocking antisense oligonucleotides (ASOs) to investigate the role of AUG codons within the antisense repeat RNA. Deletion of an AUG-containing region upstream of the antisense repeats markedly reduced poly(GP) production without affecting antisense RNA levels, demonstrating that this sequence is required for efficient poly(GP) synthesis. We further found that unspliced sense transcripts containing the repeat expansion likely serve as templates for poly(GA) and poly(GR) production in motor neurons. Finally, ASOs targeting the antisense AUG-containing region reduced poly(PR) and poly(GP) levels without altering repeat RNA abundance, supporting a role for AUG-dependent translation of the antisense repeat RNA. These findings provide new insights into the mechanisms of DPR production and suggest that translation-blocking ASOs may represent a therapeutic strategy for C9ORF72-associated ALS\/FTD.<\/jats:p>","DOI":"10.3390\/cells15181701","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T09:01:38Z","timestamp":1789981298000},"page":"1701","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["AUG-Dependent Translation of Antisense Repeat Transcripts Contributes to Dipeptide Repeat Protein Production in C9ORF72 Expansion Carriers"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5648-7239","authenticated-orcid":false,"given":"Sandra","family":"Almeida","sequence":"first","affiliation":[{"name":"Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Yuanzheng","family":"Gu","sequence":"additional","affiliation":[{"name":"Neuromuscular & Movement Disorders, Biogen, Cambridge, MA 02142, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Mark W.","family":"Kankel","sequence":"additional","affiliation":[{"name":"Neuromuscular & Movement Disorders, Biogen, Cambridge, MA 02142, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.neuron.2011.09.011","article-title":"Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS","volume":"72","author":"Mackenzie","year":"2011","journal-title":"Neuron"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1016\/j.neuron.2011.09.010","article-title":"A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD","volume":"72","author":"Renton","year":"2011","journal-title":"Neuron"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1016\/j.neuron.2013.02.004","article-title":"Unconventional translation of C9ORF72 GGGGCC expansion generates insoluble polypeptides specific to c9FTD\/ALS","volume":"77","author":"Ash","year":"2013","journal-title":"Neuron"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1007\/s00401-013-1189-3","article-title":"Bidirectional transcripts of the expanded C9orf72 hexanucleotide repeat are translated into aggregating dipeptide repeat proteins","volume":"126","author":"Mori","year":"2013","journal-title":"Acta Neuropathol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1016\/j.gde.2014.03.002","article-title":"Repeat-associated non-ATG (RAN) translation: New starts in microsatellite expansion disorders","volume":"26","author":"Cleary","year":"2014","journal-title":"Curr. 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