Phylogenetic analyses based on molecular data provide compelling evidence that ascidians are ofcritical importance for studying chordate immune system evolution. The Ciona intestinalis draftgenome sequence allows searches for phylogenetic relationships, gene cloning and expression ofimmunorelevant molecules. Acidians lack of the pivotal components of the vertebrate recombinatoryadaptive immunity, i.e., MHC, TCRs and dimeric immunoglobulins. However, bioinformatic sequenceanalyses recognized genic elements indicating the essential features of the Ig superfamily andancestor proto-MHC genes, suggesting a primitive pre-duplication and pre-recombination status. C.intestinalis genes for individuality in the absence of MHC could encode diverse molecular markers,including a wide panel of complement factors that could be responsible for self-nonself discrimination.Genome analysis reveals a number of innate immunity vertebrate-like genes which encode Toll-likeand virus receptors, complement pathways components and receptors, CD94/NK-receptor-like, lectins,TNF, IL1-R, collagens. However, pure homology seeking for vertebrate-specific immunorelevantmolecules is of limited value, and functional screening methods may be a more promising approach fortracing the immune system evolution. C. intestinalis, which displays acute and chronic inflammatoryreactions, is a model organism for studying innate immunity genes expression and functions.
|Number of pages||0|
|Journal||Invertebrate Survival Journal|
|Publication status||Published - 2009|
All Science Journal Classification (ASJC) codes
- Animal Science and Zoology