Institut de recherches cliniques de Montréal (IRCM)
Domaine : Cancer
Human DNA is about two-meter long. It therefore needs to be extensively packaged in order to fit within the cell nucleus. This packaging is performed by small proteins called histones. The sum of DNA and its associated proteins is called chromatin. DNA encodes for all the genes that makes up a human cell. In order for genes to be expressed, however, the proteins involved in their expression need to get access to the packaged DNA. Hence, there has to be a fine balance between DNA packaging and DNA accessibility. In order to deal with this problem, cells have devised strategies to ¿open up¿ DNA on demand. This is, among other things, crucial in processes such as gene expression. My laboratory stresses on understanding these mechanisms by which chromatin structure regulates gene expression. Our work is currently divided into four main projects: 1- We recently discovered that gene expression is not only regulated by chromatin but can also modify it back. We currently study mechanisms involved in this ¿molecular dialog¿ between gene expression and chromatin. 2- One of the various means by which cells regulate chromatin is by replacing regular histones with histone variants. We study the role of one of these histone variants in cell differentiation. 3- We also study the role of chromatin structure in the development of the various blood cell types. This is important since misregulation of this process can contribute to leukemia. 4- Another way by which chromatin is regulated is by the modification of histones by specific enzymes. We have undertaken to identify the target genes for a large number of these histone-modifying enzymes.