Thomas Gregor (Institut Pasteur). Biophysics Seminar ESPCI-ENS

4 May 2018 13:00 » 14:00 — A1 (Urbain)

How the physics of enhancers shapes development

Enhancers are small regulatory pieces of DNA that control the activity
of genes, which eventually determine cellular fates during the
development of multicellular organisms. They need to measure the
concentrations of various input effector molecules, called
transcription factors, and then act over often very long distances
along the DNA in order to activate a distantly located gene. There are
two two fundamental open physical problems with these enhancers: 1.
The first one is a packing problem, as a 1m long piece of DNA has to
be packed into the nucleus which is a micron-sized object. 2. The
second is a functional problem as many enhancers interact with and
compete for the same promoter for gene activation. I will present my
laboratory’s progress on both of these frontiers. We’re developing
imaging modalities that allow us to probe the 50-300nm scale at which
these interactions happen and into which thus far there is very little
optical insight. We use a combination of genome editing, live imaging
and statistical mechanics techniques to address these questions in the
developing fly embryo.