The acute transcriptional response of the coral Acropora millepora to immune challenge: expression of GiMAP/IAN genes links the innate immune responses of corals with those of mammals and plants
- Equal contributors
1 ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
2 School of Pharmacy and Molecular Sciences, James Cook University, Townsville, QLD 4811, Australia
3 Evolution, Ecology and Genetics, Research School of Biology, Australian National University, Bldg. 46, Canberra, ACT 0200, Australia
4 GeneWorks Pty Ltd, 39 Winwood Street, Thebarton, SA 5031, Australia
BMC Genomics 2013, 14:400 doi:10.1186/1471-2164-14-400Published: 14 June 2013
As a step towards understanding coral immunity we present the first whole transcriptome analysis of the acute responses of Acropora millepora to challenge with the bacterial cell wall derivative MDP and the viral mimic poly I:C, defined immunogens provoking distinct but well characterised responses in higher animals.
These experiments reveal similarities with the responses both of arthropods and mammals, as well as coral-specific effects. The most surprising finding was that MDP specifically induced three members of the GiMAP gene family, which has been implicated in immunity in mammals but is absent from Drosophila and Caenorhabditis. Like their mammalian homologs, GiMAP genes are arranged in a tandem cluster in the coral genome.
A phylogenomic survey of this gene family implies ancient origins, multiple independent losses and lineage-specific expansions during animal evolution. Whilst functional convergence cannot be ruled out, GiMAP expression in corals may reflect an ancestral role in immunity, perhaps in phagolysosomal processing.