Molecular dissection of the events leading to inactivation of the FMR1 gene
Copyright policy )Molecular dissection of the events leading to inactivation of the FMR1 gene
The analysis of a lymphoblastoid cell line (5106), derived from a rare individual of normal intelligence with an unmethylated full mutation of the FMR1 gene, allowed us to reconstruct the chain of molecular events leading to the FMR1 inactivation and to fragile X syndrome. We found that lack of DNA methylation of the entire promoter region, including the expanded CGG repeat, correlates with methylation of lysine 4 residue on the N-tail of histone H3 (H3-K4), as in normal controls. Normal levels of FMR1 mRNA were detected by real-time fluorescent RT-PCR (0.8-1.4 times compared with a control sample), but mRNA translation was less efficient (-40%), as judged by polysome profiling, resulting in reduced levels of FMRP protein (approximately 30% of a normal control). These results underline once more that CGG repeat amplification per se does not prevent FMR1 transcription and FMRP production in the absence of DNA methylation. Surprisingly, we found by chromatin immunoprecipitation that cell line 5106 has deacetylated histones H3 and H4 as well as methylated lysine 9 on histone H3 (H3-K9), like fragile X cell lines, in both the promoter and exon 1. This indicates that these two epigenetic marks (i.e. histone deacetylation and H3-K9 methylation) can be established in the absence of DNA methylation and do not interfere with active gene transcription, contrary to expectation. Our results also suggest that the molecular pathways regulating DNA and H3-K4 methylation are independent from those regulating histone acetylation and H3-K9 methylation.
- KU Leuven Belgium
- University of Rome Tor Vergata Italy
- Fondazione Santa Lucia Italy
- Catholic University of the Sacred Heart Italy
- Erasmus University Rotterdam Netherlands
Male, reactivation, pathogenesi, fragile-x-syndrome, gene amplification, immunoprecipitation, Epigenesis, Genetic, histone H4, histone H3, mark, Settore BIO/13 - BIOLOGIA APPLICATA, correlation function, exon, gene mutation, fragile X syndrome, EMC MGC-02-96-01, 11 Medical and Health Sciences, Fragile X syndrome; FMR1 gene; epigenetic modifications; DNA methylation, Genetics & Heredity, MARK, DNA methylation, protein synthesi, messenger RNA, article, METHYLATION, RNA-Binding Proteins, LYSINE-4, intelligence, priority journal, histone h3, messenger-rna, gene inactivation, lymphoblastoid cell line, fragile X mental retardation protein, Female, dna demethylation, MESSENGER-RNA, Life Sciences & Biomedicine, epigenetic, EXPRESSION, Biochemistry & Molecular Biology, 610, Nerve Tissue Proteins, 3105 Genetics, reverse transcription polymerase chain reaction, DNA DEMETHYLATION, promoter region, male, Genetic, 616, expression, Humans, controlled study, human, FRAGILE-X-SYNDROME, Gene Silencing, HISTONE H3, REACTIVATION, lysine, nucleotide repeat, fragile X mental retardation protein; histone H3; histone H4; lysine; messenger RNA; amino terminal sequence; article; controlled study; correlation function; DNA methylation; epigenetics; exon; fragile X syndrome; gene amplification; gene inactivation; gene mutation; genetic transcription; human; human cell; immunoprecipitation; intelligence; lymphoblastoid cell line; male; nucleotide repeat; nucleotide sequence; pathogenesis; polysome; priority journal; promoter region; protein synthesis; reverse transcription polymerase chain reaction; RNA translation; Epigenesis, Genetic; Female; Fragile X Mental Retardation Protein; Gene Silencing; Humans; Male; Mutation; Nerve Tissue Proteins; RNA-Binding Proteins, Science & Technology, Fragile X Messenger Ribonucleoprotein 1, RNA translation, human cell, genetic transcription, nucleotide sequence, 06 Biological Sciences, lysine-4, Nerve Tissue Protein, CELLS, Mutation, amino terminal sequence, cells, methylation, polysome, Epigenesis
Male, reactivation, pathogenesi, fragile-x-syndrome, gene amplification, immunoprecipitation, Epigenesis, Genetic, histone H4, histone H3, mark, Settore BIO/13 - BIOLOGIA APPLICATA, correlation function, exon, gene mutation, fragile X syndrome, EMC MGC-02-96-01, 11 Medical and Health Sciences, Fragile X syndrome; FMR1 gene; epigenetic modifications; DNA methylation, Genetics & Heredity, MARK, DNA methylation, protein synthesi, messenger RNA, article, METHYLATION, RNA-Binding Proteins, LYSINE-4, intelligence, priority journal, histone h3, messenger-rna, gene inactivation, lymphoblastoid cell line, fragile X mental retardation protein, Female, dna demethylation, MESSENGER-RNA, Life Sciences & Biomedicine, epigenetic, EXPRESSION, Biochemistry & Molecular Biology, 610, Nerve Tissue Proteins, 3105 Genetics, reverse transcription polymerase chain reaction, DNA DEMETHYLATION, promoter region, male, Genetic, 616, expression, Humans, controlled study, human, FRAGILE-X-SYNDROME, Gene Silencing, HISTONE H3, REACTIVATION, lysine, nucleotide repeat, fragile X mental retardation protein; histone H3; histone H4; lysine; messenger RNA; amino terminal sequence; article; controlled study; correlation function; DNA methylation; epigenetics; exon; fragile X syndrome; gene amplification; gene inactivation; gene mutation; genetic transcription; human; human cell; immunoprecipitation; intelligence; lymphoblastoid cell line; male; nucleotide repeat; nucleotide sequence; pathogenesis; polysome; priority journal; promoter region; protein synthesis; reverse transcription polymerase chain reaction; RNA translation; Epigenesis, Genetic; Female; Fragile X Mental Retardation Protein; Gene Silencing; Humans; Male; Mutation; Nerve Tissue Proteins; RNA-Binding Proteins, Science & Technology, Fragile X Messenger Ribonucleoprotein 1, RNA translation, human cell, genetic transcription, nucleotide sequence, 06 Biological Sciences, lysine-4, Nerve Tissue Protein, CELLS, Mutation, amino terminal sequence, cells, methylation, polysome, Epigenesis
selected citations These citations are derived from selected sources.This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).119 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Top 10% impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
Citations provided by BIP!Popularity provided by BIP!