Investigating MeCP2 isoform-specific expression and function
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Date
2012, 2014
Authors
Zachariah, Robby
Journal Title
Journal ISSN
Volume Title
Publisher
PLOS ONE
PLOS ONE
PLOS ONE
Abstract
Methyl CpG Binding Protein 2 (MeCP2) is an epigenetic regulator capable of recognizing and binding to methylated DNA. Mutations in MECP2 are the primary cause of Rett Syndrome (RTT) and MECP2 Duplication Syndrome (MDS). RTT is a neurodevelopmental disorder that mainly affects young females. MDS on the other hand is 100% penetrant in males and is rarely reported in females. The two disorders, although caused by extremely different etiologies, exhibit many similarities in their phenotypes including but not limited to autistic features, learning impairments and seizures. However, the molecular basis of this phenotypic similarity remains unknown. No cure has been identified to date for RTT and MDS. Alternative splicing of Mecp2/MECP2 leads to the generation of two isoforms, MeCP2E1 and MeCP2E2. Limited knowledge exists on the expression patterns and function of the two isoforms. In this thesis, I have attempted to address this knowledge gap by taking part in the validation of custom-made MeCP2 isoform-specific antibodies that are capable of differentially recognizing MeCP2E1 and MeCP2E2. Using the custom-made MeCP2E1-specific antibody, I also demonstrate that MeCP2E1 is expressed at much higher levels in neurons, as compared to astrocytes. My studies into the functional role of MeCP2 isoforms in neurons suggest that overexpression of both MECP2E1 and MECP2E2 leads to reduced rRNA levels in neurons. The potential role of MeCP2 as a negative regulator of neuronal rRNA biogenesis is further corroborated by direct binding of MeCP2 to the rDNA promoter, specifically the methylated fraction of rDNAs. Preliminary evidence from my studies suggests that MECP2 duplication in mice leads to brain region-specific alterations in rRNA levels, specifically in the cerebellum. Thus, the data presented in this thesis addresses two important knowledge gaps in the field of MeCP2 research: the higher levels of MeCP2E1 in neurons compared to astrocytes and the molecular consequences of MECP2E1 and MECP2E2 overexpression in neurons.
Description
Keywords
MeCP2, Ribosomal RNA, MeCP2-associated Disorders
Citation
Zachariah RM, Olson CO, Ezeonwuka C, Rastegar M (2012) Novel MeCP2 isoform-specific antibody reveals the endogenous MeCP2E1 expression in murine brain, primary neurons and astrocytes. PLoS One 7: e49763.
Olson CO, Zachariah RM, Ezeonwuka CD, Liyanage VR, Rastegar M (2014) Brain region-specific expression of MeCP2 isoforms correlates with DNA methylation within Mecp2 regulatory elements. PLoS One 9: e90645.
Olson CO, Zachariah RM, Ezeonwuka CD, Liyanage VR, Rastegar M (2014) Brain region-specific expression of MeCP2 isoforms correlates with DNA methylation within Mecp2 regulatory elements. PLoS One 9: e90645.