Le contrôle épigénétique de l'expression des gènes

An introduction to and definition of epigenetic control of gene expression, and its importance in normal development. We will learn what chromatin is, and how its composition and packaging can alter gene expression. We’ll also discuss the best-characterised epigenetic modification, DNA methylation, and how it is not only implicated in regulating gene expression, but also in maintaining genome stability.

We’ll discuss the molecular mechanisms for regulating gene expression in some detail, from how the DNA is packaged at a local level, right up to how the chromatin is positioned within the nucleus. We’ll learn about the chromatin modifications implicated in gene silencing and activation, the role of non-coding RNA, and higher order chromatin structures. This week will provide you with a good understanding of the basic mechanisms that will help you understand the processes we discuss throughout the rest of the course.

X chromosome inactivation is a really well-characterised epigenetic process that is now used as a model system to study epigenetic processes that are relevant more broadly. This is because it uses many epigenetic mechanisms, at many levels, to achieve really stable silencing of a whole chromosome. We’ll learn about this process and how it occurs in a mouse in great detail, which will greatly add to the mechanistic understanding gained in week two. We will then briefly discuss alternate mechanisms for dosage compensation that occur in other organisms.

We’ll learn about the two important periods during development for the erasure and resetting of the epigenome. There are two well-characterised features that are treated differently during epigenetic reprogramming; imprinted genes and repeats. We’ll learn about mechanisms for genomic imprinting, and study three examples in more depth.