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Séminaire

Jeudi 11 Octobre 2018
De 11h30 à 13h
Centre de Recherche - Paris - Amphithéâtre Biologie du développement et cancer

Gastrulation through a primitive streak : cellular mechanisms & signals

Amniote (birds and most mammals) embryos have the remarkable ability to undergo “embryonic regulation”: this is a property by which a fragment of the embryo can reconstitute the entire embryo. This can occur right up to the appearance of the primitive streak (14th day in humans), and gives rise to identical (monozygotic) twins. Understanding the mechanisms that position the primitive streak, the site of gastrulation, within the embryo is essential to understand how identical twins form. Experimental studies on chick embryos are now starting to uncover these mechanisms. A cascade of genes (including transcription factor Pitx2 and several signalling molecules like GDF1/Vg1, Nodal, BMP and Wnt) is important for primitive streak formation, but until now we have not understood the mechanisms upstream of this, which position the expression of these genes in the right place. I will review some recent work implicating some unexpected gene regulatory interactions and some non-genetic mechanisms. In parallel, we have been conducting genetic studies on human populations with a high rate of spontaneous twinning, especially in Brazil and India. The results are just starting to come out, and seem to reinforce the findings from chick experiments. In addition, the talk will highlight some important similarities and differences between non-amniotes (amphibians and fish) and higher vertebrates and how the two groups may have diverged during evolution.

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Orateur(s)

Pr Claudio Stern
Prof.

Department of Cell & Developmental Biology, University College of London (UK)

Organisateur(s)

Unit Training

Invité(e)(s) par

Allison Bardin
Domain 2 - UMR 3215 / U934 - Genetics and Developmental Biology

Institut Curie

Yohanns Bellaïche
Domain 2 - UMR 3215 / U934 - Genetics and Developmental Biology

Institut Curie

Contact

Allison Bardin

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Unit Training

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Yohanns Bellaïche

Institut Curie

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Virginie Bel Elodie Mieville

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The research in our laboratory focuses on the processes that establish cell diversity and pattern in the early embryo. We ask the questions: how do cells in the embryo know what fates to adopt, at the right positions and at the right time? What mechanisms ensure that the correct proportions of cells are allocated to different organs?

Currently, the projects in the lab fall into four major headings:

1. How do higher vertebrate embryos establish their polarity, and what mechanisms coordinate cell movements with gene expression?

2. What mechanisms are responsible for inducing the early nervous system?

3. How is the early nervous system subdivided into forebrain, midbrain, hindbrain and spinal cord?

4. Embryonic stem cells - where are they in the embryo, and can we harness them to understand developmental pathways?

We are particularly interested in discovering mechanisms that represent general principles in development, and therefore follow a multi-disciplinary approach. We choose (or if necessary, develop) techniques that will help us best to answer the questions being asked, rather than being wedded to any particular set of techniques. We do not define our questions based on specific genes, but rather based on the biological event we are trying to understand + we first define the biological process and then try to establish which genes are important for that process. Finally, although much of our research uses chick embryos (because they are easy and cheap to obtain at precise stages of development, because it is easy to manipulate cells, and because a lot is already known about how they develop), we are also not wedded to this as an experimental system. Current projects use chick, quail, frog and mouse embryos, and we are also collaborating with other labs using yeast, flies and fish.