Katrina Good

Topic

Investigation of an Uncharacterized RNA Binding Domain in the Neurodevelopment-Associated Protein Methyl CpG Binding Protein 2

Department of Biochemistry and Microbiology

Date & location

• Tuesday, February 3, 2026
• 10:00 A.M.
• Virtual Defence

Examining Committee

Supervisory Committee

• Dr. Christopher Nelson, Department of Biochemistry and Microbiology, University of Victoria (Supervisor)
• Dr. Juan Ausio, Department of Biochemistry and Microbiology, UVic (Co-Supervisor)
• Dr. John Burke, Department of Biochemistry and Microbiology, UVic (Member)
• Dr. Raad Nashmi, Department of Biology, UVic (Outside Member)

External Examiner

• Dr. Mojgan Rastegar, Department of Biochemistry and Medical Genetics, University of Manitoba

Chair of Oral Examination

• Dr. Viviene Temple, School of Exercise Science, Physical and Health Education, UVic

Abstract

Mutations in the gene encoding methyl CpG binding protein 2 (MeCP2) cause the progressive neurodevelopmental disorder Rett syndrome (RTT), for which there is currently no cure. MeCP2 is characterized as having 5 domains, although pathogenic missense mutation ‘hotspots’ cluster in the protein’s Methyl DNA binding Domain (MBD), and the NCoR Interaction Domain (NID), indicating these regions as critical for MeCP2 function. Adding to this, The MBD and NID expressed together as a peptide in RTT mice alleviates their phenotypes. Altogether, the central view of MeCP2 function is to bind methylated DNA and recruit the NCoR complex to repress gene expression. This however ignores the dozens of known MeCP2-interaction partners that involve MeCP2 in nearly all nuclear processes, indicating that there is likely some unknown facet of MeCP2 biology that can reconcile these paradoxical data. 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. The aim of the work presented in this thesis was to investigate RNA binding at this non-canonical RBD and identify how RNA interaction at this domain regulates MeCP2 function. Biochemical, biophysical, imaging, and immunoprecipitation approaches show that MeCP2-chromatin interaction is likely not regulated by RNA, but the MeCP2-protein interactome is modulated by RNA and the RBD, and interactions with the NCoR complex protein TBLR1 is negatively regulated by direct RNA interaction at the RBD. Cell-based and in vitro molecular assays that were used to validate RNA interaction at the NID/RBD of MeCP2 to a dsRNA probe in vitro and to the lncRNA NEAT1_2 in cells. Intriguingly, all the evidence gathered indicates that the NID/RBD is not the only MeCP2 RBD, as its deletion does not totally abrogate RNA binding. The work is therefore left with many important knowledge gaps to fill in future directions, including where the other MeCP2 RBD(s) is/are and their relevance to MeCP2 function and RTT. The data presented herein however, validates regulatory RNA binding at a domain known to be pathogenically sensitive and therefore may be a key part of the pathophysiology of Rett syndrome.