Chromatin and DNA methylation dynamics during retinoic acid-induced RET gene transcriptional activation in neuroblastoma cells.
Although it is well known that RET gene is strongly activated by retinoic acid (RA) in neuroblastoma cells, the mechanisms underlying such activation are still poorly understood. Here we show that a complex series of molecular events, that include modifications of both chromatin and DNA methylation state, accompany RA-mediated RET activation. Our results indicate that the primary epigenetic determinants of RA-induced RET activation differ between enhancer and promoter regions. At promoter region, the main mark of RET activation was the increase of H3K4me3 levels while no significant changes of the methylation state of H3K27 and H3K9 were observed. At RET enhancer region a bipartite chromatin domain was detected in unstimulated cells and a prompt demethylation of H3K27me3 marked RET gene activation upon RA exposure. Moreover, ChIP experiments demonstrated that EZH2 and MeCP2 repressor complexes were associated to the heavily methylated enhancer region in the absence of RA while both complexes were displaced during RA stimulation. Finally, our data show that a demethylation of a specific CpG site at the enhancer region could favor the displacement of MeCP2 from the heavily methylated RET enhancer region providing a novel potential mechanism for transcriptional regulation of methylated RA-regulated loci.
Dipartimento di Biologia e Patologia Cellulare e Molecolare and Istituto di Endocrinologia ed Oncologia Sperimentale CNR, Università degli Studi di Napoli 'Federico II' 80131 Naples, Italy.
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Angrisano
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Sacchetti
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F
Natale
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A
Cerrato
R
R
Pero
S
S
Keller
S
S
Peluso
B
B
Perillo
V E
VE
Avvedimento
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Fusco
C B
CB
Bruni
F
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Lembo
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Santoro
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Chiariotti
D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D000071221:Enhancer of Zeste Homolog 2 Protein; D044127:Epigenesis, Genetic; D056284:Histone Deacetylase 1 / Q000378:metabolism; D006801:Humans; D051783:Methyl-CpG-Binding Protein 2 / Q000378:metabolism; D009447:Neuroblastoma; D063151:Polycomb Repressive Complex 2; D011401:Promoter Regions, Genetic; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics*; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D020218:Response Elements; D000072482:Retinoic Acid Receptor alpha; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D014212:Tretinoin / Q000494:pharmacology*
D002843:Chromatin; D004268:DNA-Binding Proteins; D051783:Methyl-CpG-Binding Protein 2; C000607071:RARA protein, human; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D000072482:Retinoic Acid Receptor alpha; C099683:SIN3A transcription factor; D014157:Transcription Factors; D014212:Tretinoin; D004248:DNA (Cytosine-5-)-Methyltransferases; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D056264:Sin3 Histone Deacetylase and Corepressor Complex