Cg-Rel, the first Rel/NF-kappaB homolog characterized in a mollusk, the Pacific oyster Crassostrea gigas.
We report here the identification and functional characterization of Cg-Rel, a gene encoding the Crassostrea gigas homolog of Rel/NF-kappaB transcription factors found in insects and mammals. Sequence and phylogenetic analysis showed that Cg-Rel shares the structural organization of Rel/NF-kappaB transcription factors of class II. It includes a Rel homology domain as well as a C-terminal transactivation domain (TD). Overexpression of Cg-Rel in the Drosophila S2 cell line activated the expression of a NF-kappaB-dependent reporter gene, whereas transfection with a Cg-Rel construct containing a C-terminal deletion of the TD or using a reporter gene with mutated kappaB binding sites failed to activate expression. These results suggest that Cg-Rel is a functional member of the Rel family of transcription factors, making this the sixth structurally homologous component of the Rel/NF-kappaB pathway characterized in C. gigas. Based on homology to other invertebrates' Rel/NF-kappaB cascade, the function of the oyster pathway may serve to regulate genes involved in innate defense and/or development. These findings serve to highlight a potentially important regulatory pathway to the study of oyster immunology, hence allowing comparison of the immune system in vertebrates and invertebrates, an important key issue to understand its evolution.
Montagnani
C
C
Laboratoire de Défense et Résistance chez les Invertébrés Marins (DRIM) (IFREMER, CNRS, UMII), Université de Montpellier II, 2 place Eugène Bataillon, CC80, 34095 Montpellier, France.
Kappler
C
C
Reichhart
J M
JM
Escoubas
J M
JM
D000818:Animals; D001424:Bacterial Infections; D003001:Cloning, Molecular; D020573:Genes, rel / Q000235:genetics / Q000276:immunology; D007107:Immune System; D008974:Mollusca / Q000235:genetics / Q000276:immunology; D016328:NF-kappa B; D010125:Ostreidae / Q000235:genetics* / Q000276:immunology*; D010802:Phylogeny; D020569:Proto-Oncogene Proteins c-rel / Q000502:physiology*; D015398:Signal Transduction; D014018:Tissue Distribution; D014158:Transcription, Genetic
D016328:NF-kappa B; D020569:Proto-Oncogene Proteins c-rel