Evolutionary plasticity in the innate immune function of Akirin

Jolanta Polanowska (1) , Jia-Xuan Chen (2) , Julien Soule (1) , Shizue Omi (1) , Jérôme Belougne (1) , Clara Taffoni (1) , Nathalie Pujol (1) , Matthias Selbach (2) , Olivier Zugasti (1) , Jonathan J. Ewbank (1)

1 CIML - Centre d'Immunologie de Marseille - Luminy
2 MDC - Max Delbrück Center for Molecular Medicine [Berlin]

Eukaryotic gene expression requires the coordinated action of transcription factors, chromatin remodelling complexes and RNA polymerase. The conserved nuclear protein Akirin plays a central role in immune gene expression in insects and mammals, linking the SWI/SNF chromatin-remodelling complex with the transcription factor NFκB. Although nematodes lack NFκB, Akirin is also indispensable for the expression of defence genes in the epidermis of Caenorhabditis elegans following natural fungal infection. Through a combination of reverse genetics and biochemistry, we discovered that in C. elegans Akirin has conserved its role of bridging chromatin-remodellers and transcription factors, but that the identity of its functional partners is different since it forms a physical complex with NuRD proteins and the POU-class transcription factor CEH-18. In addition to providing a substantial step forward in our understanding of innate immune gene regulation in C. elegans, our results give insight into the molecular evolution of lineage-specific signalling pathways.

Mots clés: Caenorhabditis elegans; Epidermis; Gene regulation; Immunoprecipitation; Chromatin; Transcription factors; Gene expression; RNA interference

Domaines: Génomique, Transcriptomique et Protéomique [q-bio.GN]; Immunologie

Jolanta Polanowska, Jia-Xuan Chen, Julien Soule, Shizue Omi, Jérôme Belougne, et al.. Evolutionary plasticity in the innate immune function of Akirin. PLoS Genetics, 2018, 14 (7), pp.e1007494. ⟨10.1371/journal.pgen.1007494⟩. ⟨hal-02108805⟩