Mutant forms of MeCP2 that cause RTT retain their repressive effect on MHC class I expression.

<p>Panel A: Schematic representation of the MeCP2 protein. Red and orange arrows indicate the positions of the mutations introduced in MeCP2 by site-directed mutagenesis (MBD: methyl-CpG binding domain, TRD: transcription repression domain, WW: group II WW-domain-binding region). Panel B: N2A cells transfected with empty pcDNA3.1 (mock cells), with pcDNA3.1 expressing Myc-tagged MeCP2<i>A</i> (pMeCP2<i>A</i>-<i>myc</i>) or with pcDNA3.1 expressing Myc-tagged MeCP2<i>A</i> with the R133C point mutation (pMeCP2<i>A</i>-R133C-<i>myc</i>) were stained with mouse anti-Myc 9E10 monoclonal antibody, and FITC-labelled anti-mouse IgG antibody. Coverslips were mounted in DAPI-containing ProLong Gold antifade reagent (Molecular Probes) before observation by fluorescence microscopy. Panel C: N2A cells transfected as in panel B were double immunostained for cell surface MHC class I and intracellular Myc-tagged MeCP2, then analysed by flow cytometry. Similar data were obtained for all four mutated forms of MeCP2<i>A</i> and MeCP2<i>B</i> (not shown), and these observations were reproduced in three independent transfection experiments.