The main interest of the Poulin lab is to understand how signalling events occurring in the extracellular space can produce a response inside the cell to impact on the chromatin structure. This can release the transcriptional machinery for activation or prevent its engagement for repression. This complex process requires directed alterations of the chromatin structure via remodeling, deposition or removal of chemical modifications on histone tails. Malfunction in this chain of events, from the signal to chromatin alterations, impacts on totipotency, cell differentiation, stress responses, and ageing.