The present invention provides methods for discovering agents that are effective in reversing epigenetic silencing by inhibiting the interaction of methyl-binding (MBD) proteins with methylated genomic DNA. Also provided are methods for reactivating silenced genes having CpG island hypermethylation along with methods for treatment and prevention of diseases, such as cancer and sickle cell anemia, by administering an agent that modulates methyl-binding domain (MBD) protein-mediated transcriptional repression, thereby increasing gene transcription to prevent or treat disease. Additionally, compounds identified by the present invention useful for treatment and prevention of diseases, such as cancer and sickle cell anemia, are provided.