Cargando…
Role of CTCF Protein in Regulating FMR1 Locus Transcription
Fragile X syndrome (FXS), the leading cause of inherited intellectual disability, is caused by epigenetic silencing of the FMR1 gene, through expansion and methylation of a CGG triplet repeat (methylated full mutation). An antisense transcript (FMR1-AS1), starting from both promoter and intron 2 of...
Autores principales: | , , , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3715420/ https://www.ncbi.nlm.nih.gov/pubmed/23874213 http://dx.doi.org/10.1371/journal.pgen.1003601 |
_version_ | 1782277450055548928 |
---|---|
author | Lanni, Stella Goracci, Martina Borrelli, Loredana Mancano, Giorgia Chiurazzi, Pietro Moscato, Umberto Ferrè, Fabrizio Helmer-Citterich, Manuela Tabolacci, Elisabetta Neri, Giovanni |
author_facet | Lanni, Stella Goracci, Martina Borrelli, Loredana Mancano, Giorgia Chiurazzi, Pietro Moscato, Umberto Ferrè, Fabrizio Helmer-Citterich, Manuela Tabolacci, Elisabetta Neri, Giovanni |
author_sort | Lanni, Stella |
collection | PubMed |
description | Fragile X syndrome (FXS), the leading cause of inherited intellectual disability, is caused by epigenetic silencing of the FMR1 gene, through expansion and methylation of a CGG triplet repeat (methylated full mutation). An antisense transcript (FMR1-AS1), starting from both promoter and intron 2 of the FMR1 gene, was demonstrated in transcriptionally active alleles, but not in silent FXS alleles. Moreover, a DNA methylation boundary, which is lost in FXS, was recently identified upstream of the FMR1 gene. Several nuclear proteins bind to this region, like the insulator protein CTCF. Here we demonstrate for the first time that rare unmethylated full mutation (UFM) alleles present the same boundary described in wild type (WT) alleles and that CTCF binds to this region, as well as to the FMR1 gene promoter, exon 1 and intron 2 binding sites. Contrariwise, DNA methylation prevents CTCF binding to FXS alleles. Drug-induced CpGs demethylation does not restore this binding. CTCF knock-down experiments clearly established that CTCF does not act as insulator at the active FMR1 locus, despite the presence of a CGG expansion. CTCF depletion induces heterochromatinic histone configuration of the FMR1 locus and results in reduction of FMR1 transcription, which however is not accompanied by spreading of DNA methylation towards the FMR1 promoter. CTCF depletion is also associated with FMR1-AS1 mRNA reduction. Antisense RNA, like sense transcript, is upregulated in UFM and absent in FXS cells and its splicing is correlated to that of the FMR1-mRNA. We conclude that CTCF has a complex role in regulating FMR1 expression, probably through the organization of chromatin loops between sense/antisense transcriptional regulatory regions, as suggested by bioinformatics analysis. |
format | Online Article Text |
id | pubmed-3715420 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-37154202013-07-19 Role of CTCF Protein in Regulating FMR1 Locus Transcription Lanni, Stella Goracci, Martina Borrelli, Loredana Mancano, Giorgia Chiurazzi, Pietro Moscato, Umberto Ferrè, Fabrizio Helmer-Citterich, Manuela Tabolacci, Elisabetta Neri, Giovanni PLoS Genet Research Article Fragile X syndrome (FXS), the leading cause of inherited intellectual disability, is caused by epigenetic silencing of the FMR1 gene, through expansion and methylation of a CGG triplet repeat (methylated full mutation). An antisense transcript (FMR1-AS1), starting from both promoter and intron 2 of the FMR1 gene, was demonstrated in transcriptionally active alleles, but not in silent FXS alleles. Moreover, a DNA methylation boundary, which is lost in FXS, was recently identified upstream of the FMR1 gene. Several nuclear proteins bind to this region, like the insulator protein CTCF. Here we demonstrate for the first time that rare unmethylated full mutation (UFM) alleles present the same boundary described in wild type (WT) alleles and that CTCF binds to this region, as well as to the FMR1 gene promoter, exon 1 and intron 2 binding sites. Contrariwise, DNA methylation prevents CTCF binding to FXS alleles. Drug-induced CpGs demethylation does not restore this binding. CTCF knock-down experiments clearly established that CTCF does not act as insulator at the active FMR1 locus, despite the presence of a CGG expansion. CTCF depletion induces heterochromatinic histone configuration of the FMR1 locus and results in reduction of FMR1 transcription, which however is not accompanied by spreading of DNA methylation towards the FMR1 promoter. CTCF depletion is also associated with FMR1-AS1 mRNA reduction. Antisense RNA, like sense transcript, is upregulated in UFM and absent in FXS cells and its splicing is correlated to that of the FMR1-mRNA. We conclude that CTCF has a complex role in regulating FMR1 expression, probably through the organization of chromatin loops between sense/antisense transcriptional regulatory regions, as suggested by bioinformatics analysis. Public Library of Science 2013-07-18 /pmc/articles/PMC3715420/ /pubmed/23874213 http://dx.doi.org/10.1371/journal.pgen.1003601 Text en © 2013 Lanni 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, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Lanni, Stella Goracci, Martina Borrelli, Loredana Mancano, Giorgia Chiurazzi, Pietro Moscato, Umberto Ferrè, Fabrizio Helmer-Citterich, Manuela Tabolacci, Elisabetta Neri, Giovanni Role of CTCF Protein in Regulating FMR1 Locus Transcription |
title | Role of CTCF Protein in Regulating FMR1 Locus Transcription |
title_full | Role of CTCF Protein in Regulating FMR1 Locus Transcription |
title_fullStr | Role of CTCF Protein in Regulating FMR1 Locus Transcription |
title_full_unstemmed | Role of CTCF Protein in Regulating FMR1 Locus Transcription |
title_short | Role of CTCF Protein in Regulating FMR1 Locus Transcription |
title_sort | role of ctcf protein in regulating fmr1 locus transcription |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3715420/ https://www.ncbi.nlm.nih.gov/pubmed/23874213 http://dx.doi.org/10.1371/journal.pgen.1003601 |
work_keys_str_mv | AT lannistella roleofctcfproteininregulatingfmr1locustranscription AT goraccimartina roleofctcfproteininregulatingfmr1locustranscription AT borrelliloredana roleofctcfproteininregulatingfmr1locustranscription AT mancanogiorgia roleofctcfproteininregulatingfmr1locustranscription AT chiurazzipietro roleofctcfproteininregulatingfmr1locustranscription AT moscatoumberto roleofctcfproteininregulatingfmr1locustranscription AT ferrefabrizio roleofctcfproteininregulatingfmr1locustranscription AT helmercitterichmanuela roleofctcfproteininregulatingfmr1locustranscription AT tabolaccielisabetta roleofctcfproteininregulatingfmr1locustranscription AT nerigiovanni roleofctcfproteininregulatingfmr1locustranscription |