Figure 5.

Major epigenetic modifications at the FMR1 locus after histone acetylating treatments. In anormally active WT allele a permissive euchromatic configuration is present (bottom), while in methylated full mutation (FXS) the heterochromatic configuration does not allow transcription (top). The use of L-acetylcarnitine (LAC) on FXS induces an increase of H3 and H4 acetylation without DNA demethylation and transcriptional reactivation (middle left). Valproic acid (VPA) treatment shows a slight transcriptional activity with hyperacetylation of H3 and H4 and methylation of H3K4, while H3K9 methylation remains unmodified. MBD, methyl-binding domain protein; HD, histone deacethylases; Ac, histone acetyl groups.