• Laila Kobrossy, Ph.D.
• Postdoctoral Fellow
• laila[at]mcb[dot]harvard[dot]edu

The role of DNA Replication in the Reversal of PcG-dependent Hox Gene Silencing

Since DNA replication is coupled to a reconfiguration in chromatin states, it has been speculated to play a central role in epigenetic re-programming and transformation of cell fates. During embryonic development and cellular differentiation, PcG and Trx protein families play an essential role in maintaining stable transcriptional states, including those of HOX genes. Under some circumstances, such as differentiation, these states are switched (for example from repressed to activated). To understand how PcG and trxG regulation interfaces with the cell cycle, and to provide a model system for addressing the general question of the role of DNA replication in changing transcription states, I am investigating the role of DNA replication in differentiation induced activation of HOX genes. Specifically, differentiation induced activation involves a switch from PcG to trxG regulation and I am asking whether and how DNA replication facilitates or is required for this switch. I am using a mammalian cell culture system to study the dynamics of PcG- and TrxG-protein binding at different stages of the cell cycle before, during, and following gene activation.