Mécanismes biochimiques de l'héritabilité épigénétique

 

Nicole Francis

Institut de recherches cliniques de Montréal (IRCM)

 

Domaine : cancer

Programme : Chercheurs-boursiers - Senior

Concours 2016-2017

 

 Nearly every cell in our bodies contains our full genetic blueprint (DNA), but each cell uses only a small part of the blueprint to direct its function. During development, cells that form different tissues and organs receive instructions about which part of the blueprint to use. They organize their DNA so that parts that will be used are easy to access, while parts that aren't needed are stashed away. Thus different cells have the same DNA organized in different ways. DNA organization is carried out by proteins that bind DNA. The structure formed by these proteins and the DNA is called chromatin.

Polycomb Group (PcG) proteins are special chromatin proteins that are important for remembering chromatin organization in different cells. They were discovered in fruit flies in the 1940s, and subsequently in mammals as proteins that promote tumour formation.  Many additional studies have verified that PcG proteins play a central role in many different cancers but are also important for many aspects of normal development in mammals, as in flies. Thus, how cells remember who they are and how cells become cancerous are related processes that are controlled by chromatin proteins.

Each time a cell divides, it needs to duplicate its chromatin organization so that the same parts of the genetic blueprint are used by the two new cells. We are studying how chromatin structure can be duplicated when cells divide.  PcG proteins are thought to be important for this process.  To understand how this can occur at a molecular level, we recreate the behavior of chromatin and PcG proteins during cell division in test tubes. Understanding how PcG proteins remember chromatin packaging will help us understand how and why chromatin is disrupted in cancer and may identify new therapeutic approaches to cancer.