MeCP2 NID interaction with RNA: Implications for Rett Syndrome-Relevant Protein Regulation

Mutations in the MECP2 gene cause the progressive neurodevelopmental disorder Rett syndrome. Pathogenic missense mutation hotspots exist in the proteins Methyl DNA binding Domain (MBD), and the NCoR Interaction Domain (NID), indicating these regions as critical for MeCP2 function. The NID binds to a co-repressor complex allowing transcriptional repression at target genes. A putative RNA Binding Domain (RBD) was identified that overlaps with the NID, yet the role that RNA interaction plays in MeCP2 function remains underexplored. Using cell-based and in vitro molecular assays, we validated RNA interaction at the NID/RBD of MeCP2 both to a dsRNA probe in vitro and to the lncRNA NEAT1_2 in cells. As expected, this region did not appear to affect MeCP2-chromatin interactions; however, we found that RNA-RBD interaction precludes MeCP2-NCoR binding in cells. Taken together, we find that RNA interaction at this non-canonical RNA binding domain regulates important MeCP2-protein interactions and therefore may be a key part of the pathophysiology of Rett syndrome.