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Decembre 2022



Amphi G2, UCBL

Séminaire Externe

« Structural and functional analysis of bunyavirus replication and transcription »

Hélène MALET (Université Grenoble Alpes – Institut de Biologie Structurale, Groupe Microscopie Electronique et Méthodes)
Hôte : Pierre-Yves Lozach
The Bunyavirales is a very large order of segmented negative-stranded RNA viruses (sNSV). Among them, there are many human and animal pathogens against which no drug is currently available (Lassa, Hantaan, La Crosse viruses). In this context, we aim at understanding the mechanisms underlying two key steps of the viral cycle: replication and transcription of the viral genome. These processes are carried out by the viral polymerase that interacts with the RNA encapsidated by nucleoproteins.
To understand how nucleoproteins interact with each other to protect their RNA, I will describe the structure of the Hantaan nucleocapsid determined at 3 Å resolution by cryo-EM. I will present the cryo-EM structure of La Crosse virus polymerase that uncovers the organization of this essential enzyme. I will also show how replication and transcription assays coupled with high-resolution cryo-EM eventually led to the determination of 7 structures of La Crosse virus polymerase stalled at specific key active stages, revealing the large conformational changes that are necessary for activity.

Jeudi 01/12/2022

Amphi Pasteur

Séminaire Externe

 «The Winner Takes it All, and COVID19 Likes to Win – Dynamics of Viral Replication vs. Cell-Intrinsic Immunity»

Marco BINDER (Lab director "Dynamics of early viral infection and the innate antiviral response" German Cancer Research Center (DKFZ), Heidelberg - RFA)
Hôte : Marlène Dreux
We previously observed a primed state of epithelial cells in the upper airway epithelial cells of children prior to infection, characterized by a higher expression level of RLRs, in particular MDA5, as compared to adults (Loske et al., Nat Biotech 2022). This sensitized state was associated with a rapid and robust induction of an IFN signature across epithelial and immune cell types upon SARS-CoV-2 infection. We hence speculate that subtle differences in the set-point of the virus sensing machinery in epithelial cells would have a decisive role in the successful mounting of an IFN response. Here, we report that indeed priming of epithelial A549 cells with low-moderate doses of type I IFN or select inflammatory cytokines sensitizes their RLR pathway sufficiently to produce robust levels of type I and III IFNs upon SARR-CoV-2 infection. We confirm MDA5 as the major sensor, however, we also find a substantial contribution of RIG-I. Wondering why specifically children’s epithelial cells would exhibit this primed state, we looked into the involvement of immune cells. We found microbially stimulated immune cells (PBMCs) of children to be able to induce stronger RLR expression in A549 cells than PBMCs of adults, sufficient to enable a robust IFN induction upon SARS-CoV-2 infection. This immune-epithelial cell interaction was mediated by both type I IFN as well as distinct pro-inflammatory cytokines. Our scRNA-Seq data revealed that this in vitro finding corresponds to the physiological situation, with mucosal immune cells of children exhibiting higher levels of those cytokines at baseline, likely explaining the antiviral priming of their epithelial cells

Lundi 05/12/2022


Séminaire Externe

« title tbc »

Filipe BORGES (Institut Jean-Pierre Bourgin, INRAe)
Host : Daniel Bouyer

Mardi 06/12/2022


Amphi médiathèque Paul Zech, Faculté Rockefeller

Séminaire Externe

4ème journée scientifique

Fédération d’Immunopathologie de Lyon (LIFe)
Contact : Alice Koenig
La Fédération d’Immunopathologie de Lyon (LIFe) a le plaisir de vous informer de la tenue de sa 4ème journée scientifique, le mardi 6 décembre 2022 à la médiatèque Paul Zech, Faculté de médecine Lyon Est – Rockefeller (UCBL – Lyon 1).
Cette 4ème journée sera l’occasion de partager les travaux scientifiques en immunologie clinique et translationnelle des praticiens et chercheurs de LIFE.
Nous aurons également l’honneur d’accueillir deux experts de ce domaine : le Dr Paul BASTARD (Institut hospitalo-universitaire Imagine – AP-HP/Paris cité) et le Pr Julien ZUBER (Hôpital Necker-Enfants Malades) pour des conférences dédiées respectivement à la prédisposition génétique aux infections virales sévères et au rejet humoral du fœtus. Vous retrouverez le programme complet de cette journée en pièce jointe.
La 4ème journée scientifique de LIFe est ouverte à tous, médecins, étudiants et chercheurs. Comme chaque année, nous vous attendons nombreux, mais attention, inscrivez-vous vite, les places sont limitées (inscription gratuite mais obligatoire)

Mardi 06/12/2022


Amphi Pasteur

Séminaire externe

 « Viral Evolution & Vaccine Design »

Morgane ROLLAND  (U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA)
 Hôte : Lionel Condé
RNA viruses include some of the most rapidly evolving pathogens and pathogen diversity is a significant obstacle to developing effective vaccines. The enormous diversity of HIV-1 has challenged vaccine efforts for almost four decades, and the succession of SARS-CoV-2 variants that have emerged since 2021 can threaten the effectiveness of current vaccines. Here we will contrast evolutionary processes for HIV-1 and SARS-CoV-2, describing how both viruses evolve and adapt to the host immune response. Then, we will discuss how evolutionary dynamics are integrated to optimize vaccine candidates. We will present new vaccine design strategies for HIV-1 and coronaviruses and show how computational models can help design better vaccine candidates capable of targeting both current and future threats.

Mardi 08/12/2022


Amphi Pasteur

Séminaire externe

 « RNA queuosine modification and response to antibiotics in Vibrio cholerae »

Dr. Zeynep BAHAROGLU (Institut Pasteur - Unité "Plasticité du Génome Bactérien" - Département Génomes et Génétique)
 Hôte : Karen Moreau
Antibiotic overuse and misuse in clinical and farming contexts contribute to resistance development, during treatment of infection, but also as antibiotic gradients in soil and water, the natural reservoir of many bacteria. Using such non lethal antibiotic doses, we have linked 23 tRNA and rRNA modification enzymes with specific responses to various antibiotics in V. cholerae. We further studied the molecular mechanisms underlying this specificity in the absence of tgt/queuosine (Q) modification. We showed that (i) the absence of Q impacts tyrosine codon decoding and leads to translational reprogramming in response to stress. (ii) A protein's codon usage bias can influence its translation in a Q modification dependent way. (iii) Candidate transcripts subject to modification tunable translation can be identified in silico based on their codon content in bacteria. Our results highlight the existence of an epitranscriptomic and translational control of the bacterial response to antibiotic stress

Vendredi 16/12/2022



Séminaire externe
« On the multiple roads to cell fate decision: integrating transcription factors into RNA-regulatory networks »


Julie CARNESECCHI (IGFL)                                        
Hôte : Gael Yvert









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