Our group regularly invites biologists to give talks at the University of Bordeaux.
- April 6th, 2016 (11am-12pm): Philippe Horvath (DuPont):
Discovered in 2007, CRISPR-Cas is a bacterial immunity system directed against nucleic acids, notably viral DNA. In this system, the immunological memory is built through the acquisition of short viral DNA sequences into the chromosome of the bacterial host, within peculiar regions called CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats). In the interference stage, these sequences are transcribed into small RNA molecules named crRNAs, that are used by Cas (CRISPR-associated) proteins to recognize and inactivate any foreign DNA showing sequence complementary to the crRNAs. The ability of certain Cas proteins, notably Cas9, to be directed by a short RNA towards a DNA target and to cleave it at a precise position has been diverted and transformed in 2012 into a simple and efficient tool for genome editing. Since then, the Cas9 tool has been applied successfully to genome modification of numerous organisms, including microorganisms, plants, animals, and humans. This presentation will focus on the milestone and fundamental discoveries about CRISPR-Cas systems, and on some of their applications.Philippe Horvath played a very important role in the discovery of the CRISPR-Cas system:
- November 17, 2015: Bruno Lemaitre (Ecole polytechnique fédérale de Lausanne)
Drosophila immunity: an overview
The application of Drosophila genetics to these mechanisms has generated insights into insect immunity and uncovered general principles of animal host defense. These studies have shown that Drosophila has multiple defense “modules” that can be deployed in a coordinated response against distinct pathogens. Today, Drosophila can be considered as having one of the best-characterized host defense systems among the metazoan. This seminar will provide an overview of the Drosophila immune responses underlining new findings and questions.
- October 14, 2015: Eric Vivier (Directeur du Centre d'immunologie de Marseille-Luminy)
On Innate Lymphoid cell signature, plasticity and redundancy
(Site Carreire, Amphithéâtre 12)
ILCs are a new type of lymphocytes, and their study is an emerging field in immunology that is having a major effect on our understanding of immune responses. However, much remains to be understood regarding the role of ILCs in humans and mice, particularly given the diversity of ILCs, which adds to the complexity of their analysis. ILCs can be classified into cytotoxic ILCs, such as NK cells, and helper-like ILCs, such as the ILC1, ILC2 and ILC3 subsets. The study of ILC2 cells has progressed considerably in recent years, due particularly to the development of mouse models selectively targeting these cells, such as RORalpha-deficient mice. By contrast, much remains unknown about the respective roles of NK, ILC1 and ILC3 cells. NK cells, ILC1 and NCR+ILC3 are known to express NKp46 in humans and mice. We will present here recent findings on the transcriptomic signature of NKp46+ ILCs, on their plasticity as well as on their role in natura.
- December 11, 2014: Anthony W. De Tomaso (Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, USA)
Allorecognition and Stem Cell Parasitism- the strange life of a basal chordate.
The key event in adaptive immune function is the ability to discriminate between alleles of a highly polymorphic family of proteins called the MHC, by a diverse set of both adaptive (T-cell) and innate (NK-cell) receptors. These recognition events were originally discovered by studies in histocompatibility (both solid organ and bone marrow), the process responsible for the rejection of transplanted tissues. While no orthologs of the MHC or cognate receptors exist in pre-vertebrates, the process of histocompatibility does, and there are well-studied system found in both unicellular organisms and throughout the metazoa, from the simplest (marine sponges) to humans. How does allorecognition work in these primitive organisms, and why is histocompatibility so widespread?
My lab is studying an organism that provides insight into both of these questions: a basal chordate called Botryllus schlosseri. The first part of my talk will focus on the molecular mechanisms underlying histocompatibility in Botryllus, which resembles the missing-self recognition strategy used by mammalian NK cells, and represents a simplified model to study the development and maintenance of immune tolerance. The second part of my talk will focus on why allorecognition exists in Botryllus, which involves a unique characteristic: the natural transplantation of parasitic germline stem cells. Here I will talk about recent data on prospective isolation and molecular characterization of these germline stem cells, as well as the role of the S1P pathway in controlling homing.