FMR1 and fragile X syndrome: Further, although only vorinostat, but not trichostatin A, corrected the FXS-associated behavioral symptoms, they both effectively caused significant increase of H2B (Fig. 7A2 and A4, B2 and B4) and H3 acetylation (Fig. 7A3 and A5, B3 and B5) in the hippocampus (Fig. 7A2 and A3, B2 and B3) and prefrontal cortex (Fig. 7A4 and A5, A4 and B5) of WT and Fmr1 KO mice.