The role of MeCP2 in transcriptional regulation. (A) Upon binding to methylated CpG di-nucleotides (5mC), MeCP2 recruits repressor complexes such as mSIN3A, HDACs, and NCoR-SMRT to suppress gene transcription. (B) Upon binding to 5hmC, MeCP2 interacts with CREB to promote transcriptional activation and recruitment of other activators. (C) DNMTs add methyl groups onto the fifth carbon of cytosine residues in the CpG di-nucleotides to form 5mC, whereas TET enzymes oxidize the methyl groups to form 5hmC. 5hmC: 5-hydroxymethylcytosine; 5mC: 5-methylcytosine; CREB: cAMP response element binding protein; DNMTs: DNA methyltransferases; HDACs: histone deacetylases; mSIN3A: mammalian switch-independent 3A; MeCP2: methyl-CpG binding protein 2; NCoR: nuclear receptor corepressor; SMRT: silencing mediator for retinoid and thyroid hormone receptors; TET: ten–eleven translocation. Information obtained from [13,15,53,54,64,87,92,93,94]. Figure is created with BioRender.com.