Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length

Abstract Background Reduced copy number of the D4Z4 macrosatellite at human chromosome 4q35 is associated with facioscapulohumeral muscular dystrophy (FSHD). A pervasive idea is that chromatin alterations at the 4q35 locus following D4Z4 repeat unit deletion lead to disease via inappropriate express...

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Main Authors: Valentina Salsi, Francesca Losi, Monica Salani, Paul D. Kaufman, Rossella Tupler
Format: Article
Language:English
Published: BMC 2025-05-01
Series:Clinical Epigenetics
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Online Access:https://doi.org/10.1186/s13148-025-01881-5
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author Valentina Salsi
Francesca Losi
Monica Salani
Paul D. Kaufman
Rossella Tupler
author_facet Valentina Salsi
Francesca Losi
Monica Salani
Paul D. Kaufman
Rossella Tupler
author_sort Valentina Salsi
collection DOAJ
description Abstract Background Reduced copy number of the D4Z4 macrosatellite at human chromosome 4q35 is associated with facioscapulohumeral muscular dystrophy (FSHD). A pervasive idea is that chromatin alterations at the 4q35 locus following D4Z4 repeat unit deletion lead to disease via inappropriate expression of nearby genes. Here, we sought to analyze transcription and chromatin characteristics at specific regions of 4q35 and how these are affected by D4Z4 deletions and exogenous stresses. Results We found that the 4q subtelomere is subdivided into discrete domains, each with characteristic chromatin features associated with distinct gene expression profiles. Centromeric genes within 4q35 (SLC25A4, FAT1 and FRG1) display active histone marks at their promoters. In contrast, poised or repressed markings are present at telomeric loci including FRG2, DBE-T and D4Z4. We discovered that these discrete domains undergo region-specific chromatin changes upon treatment with chromatin enzyme inhibitors or genotoxic drugs. We demonstrated that the 4q35 telomeric FRG2, DBE-T and D4Z4-derived transcripts are induced upon DNA damage to levels inversely correlated with the D4Z4 repeat number, are stabilized through posttranscriptional mechanisms upon DNA damage and are bound to chromatin. Conclusion Our study reveals unforeseen biochemical features of RNAs from clustered transcription units within the 4q35 subtelomere. Specifically, the FRG2, DBE-T and D4Z4-derived transcripts are chromatin-associated and are stabilized posttranscriptionally after induction by genotoxic stress. Remarkably, the extent of this response is modulated by the copy number of the D4Z4 repeats, raising new hypotheses about their regulation and function in human biology and disease.
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spelling doaj-art-771c086c3fd84cd08061ec99e7d045bc2025-08-20T03:52:24ZengBMCClinical Epigenetics1868-70832025-05-0117111710.1186/s13148-025-01881-5Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat lengthValentina Salsi0Francesca Losi1Monica Salani2Paul D. Kaufman3Rossella Tupler4Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio EmiliaDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio EmiliaCenter for Human Genetic Research, Massachusetts General Hospital Research Institute and Department of Neurology, Harvard Medical SchoolDepartment of Molecular, Cell and Cancer Biology, University of Massachusetts Medical SchoolDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio EmiliaAbstract Background Reduced copy number of the D4Z4 macrosatellite at human chromosome 4q35 is associated with facioscapulohumeral muscular dystrophy (FSHD). A pervasive idea is that chromatin alterations at the 4q35 locus following D4Z4 repeat unit deletion lead to disease via inappropriate expression of nearby genes. Here, we sought to analyze transcription and chromatin characteristics at specific regions of 4q35 and how these are affected by D4Z4 deletions and exogenous stresses. Results We found that the 4q subtelomere is subdivided into discrete domains, each with characteristic chromatin features associated with distinct gene expression profiles. Centromeric genes within 4q35 (SLC25A4, FAT1 and FRG1) display active histone marks at their promoters. In contrast, poised or repressed markings are present at telomeric loci including FRG2, DBE-T and D4Z4. We discovered that these discrete domains undergo region-specific chromatin changes upon treatment with chromatin enzyme inhibitors or genotoxic drugs. We demonstrated that the 4q35 telomeric FRG2, DBE-T and D4Z4-derived transcripts are induced upon DNA damage to levels inversely correlated with the D4Z4 repeat number, are stabilized through posttranscriptional mechanisms upon DNA damage and are bound to chromatin. Conclusion Our study reveals unforeseen biochemical features of RNAs from clustered transcription units within the 4q35 subtelomere. Specifically, the FRG2, DBE-T and D4Z4-derived transcripts are chromatin-associated and are stabilized posttranscriptionally after induction by genotoxic stress. Remarkably, the extent of this response is modulated by the copy number of the D4Z4 repeats, raising new hypotheses about their regulation and function in human biology and disease.https://doi.org/10.1186/s13148-025-01881-5D4Z4 chromatin signatureDNA damageEpigenetic regulationFSHD
spellingShingle Valentina Salsi
Francesca Losi
Monica Salani
Paul D. Kaufman
Rossella Tupler
Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length
Clinical Epigenetics
D4Z4 chromatin signature
DNA damage
Epigenetic regulation
FSHD
title Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length
title_full Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length
title_fullStr Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length
title_full_unstemmed Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length
title_short Posttranscriptional RNA stabilization of telomeric RNAs FRG2, DBE-T, D4Z4 at human 4q35 in response to genotoxic stress and D4Z4 macrosatellite repeat length
title_sort posttranscriptional rna stabilization of telomeric rnas frg2 dbe t d4z4 at human 4q35 in response to genotoxic stress and d4z4 macrosatellite repeat length
topic D4Z4 chromatin signature
DNA damage
Epigenetic regulation
FSHD
url https://doi.org/10.1186/s13148-025-01881-5
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