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Elina Aleksejeva a le plaisir de vous convier à sa soutenance de thèse intitulée : "Défenses innées antivirales du poisson zèbre: de la signalisation aux cellules spécialisées". La présentation sera en anglais.

La soutenance aura lieu le mercredi 20 Janvier 2016 à 14h00 dans l’amphithéâtre du bâtiment 440 à l’INRA de Jouy-en-Josas.

Abstract

This thesis is based on the studies of two aspects of innate immunity in zebrafish: 1) proteins involved in the regulation of type I interferon (Ifn) and 2) specialized myeloid cells that patrol neuromasts – mechano-sensory organs embed in the skin that could be pathogen entry sites. In this thesis two different proteins are described for the capability to enhance Ifn production. In one part, two zebrafish orthologues of mammalian transcription factor PLZF (Promyelocytic leukemia zinc finger) are shown to augment type I Ifn and ISG in response to double-stranded RNA viruses. PLZF is a BTB/POZ transcription factor that was recently shown to induce a subset of ISG, in human and mouse. Thus, zebrafish Plzf proteins can operate at multiple steps in the Ifn system. Furthermore, their activity was not dependent on the presence of BTB-domain implying that the underlying mechanism is different from the usual mode of action of BTB/POZ transcription factors. In the second part, fish-specific TRIM ubiquitin ligase - Ftr83 (Fish novel tripartite motif protein 83), mounted a strong anti-viral protection through the upregulation of Ifn. Interestingly a strong correlation between the expression of Ftr83 and Ifn was seen in the gills suggesting that Ftr83 might maintain a low basal level of Ifn signalling in organs constantly exposed to pathogens. In the second part, a GFP reporter transgenic line called medaktin:EGFP has been characterized. It marks leukocytes in the skin surrounding neuromasts. Deep sequencing revealed that these cells express several macrophage and dendritic cell markers, including genes involved in autophagy, microbicidial functions and antigen presentation, thus highlighting them as possible sentinel cells.