Unraveling the Interaction of BRD4 and MeCP2 in Epigenetic Gene Regulation

Sowmya, Sowmya (2025) Unraveling the Interaction of BRD4 and MeCP2 in Epigenetic Gene Regulation. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Sowmya (20MS200)) 20MS200_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

BRD4 and MeCP2 are key epigenetic readers, with BRD4 functioning as a reader of acetylated lysine residues via its two bromodomains (BD1 and BD2), and MeCP2 primarily acting as a methyl-DNA binding protein that modulates chromatin structure and transcription. Recent studies have hinted at possible interaction between these proteins, but the molecular mechanisms and the functional implications of their interaction remain poorly understood. This thesis aims to unravel the nature and significance of the interaction between BRD4 and MeCP2, employing an integrated approach that includes molecular modeling, biochemical validation, and genomic data analysis. Initially, molecular docking and molecular dynamics simulations were performed to investigate the binding interactions between BRD4 BD1 and BD2 and various acetylated peptides derived from MeCP2. These computational studies revealed stable and specific interactions, with domain-selective affinities that suggested a potential regulatory mechanism dependent on MeCP2 acetylation status. To validate these findings experimentally, isothermal titration calorimetry (ITC) was conducted using tri-acetylated MeCP2 peptides and purified BRD4 bromodomains. The ITC results confirmed a direct, domain-specific interaction, characterized by favorable binding enthalpies and dissociation constants consistent with high-affinity recognition. Further, co-immunoprecipitation assays in HEK293T cells demonstrated that full-length BRD4 and MeCP2 interact endogenously, providing crucial evidence of their association in a cellular context and supporting the physiological relevance of the in vitro findings. To understand how the BRD4–MeCP2 interaction affects gene regulation in cancer, ChIP-seq and RNA-seq data from colon cancer cell lines were analyzed. The results showed that BRD4 and MeCP2 often bind to the same regions of the genome, especially at sites controlling genes linked to cell growth, transcription, and immune function. This study highlights that acetylation of MeCP2 may help recruit BRD4 to specific genes, influencing their activity. Overall, these findings shed light on how BRD4 and MeCP2 cooperate in cancer and suggest they could be targeted together in future therapies.

Actions (login required)

View Item