Fig. 2

MeCP2 regulates long gene expression in a 5mCA-dependent manner. The 5mCG mark is commonly found enriched at gene promotor regions, while the 5mCA mark is enriched in the gene bodies of exceptionally long genes (>100 kb) in neurons. The epigenetic “reader” MeCP2 binds both marks, but has a strong affinity for 5mCA in long gene bodies. In wild-type neurons, this interaction represses transcription of long genes and may allow for fine tuning of gene expression. Currently, the machinery and mechanism by which MeCP2 silences long genes is unknown. In the Mecp2 null neuron, 5mCA marks in long genes go unrecognized and the locus is aberrantly transcribed