Xenopus Interferon Complex: Inscribing the Amphibiotic Adaption and Species-Specific Pathogenic Pressure in Vertebrate Evolution?

Yun Tian,Jordan Jennings,Yongming Sang,Yuanying Gong

doi:10.3390/cells9010067

Abstract

Several recent studies have revealed previously unknown complexity of the amphibian interferon (IFN) system. Being unique in vertebrate animals, amphibians not only conserve and multiply the fish-like intron-containing IFN genes, but also rapidly evolve amniote-like intronless IFN genes in each tested species. We postulate that the amphibian IFN system confers an essential model to study vertebrate immune evolution in molecular and functional diversity to cope with unprecedented pathophysiological requirement during terrestrial adaption. Studies so far have ascribed a potential role of these IFNs in immune regulation against intracellular pathogens, particularly viruses; however, many knowledge gaps remain elusive. Based on recent reports about IFN’s multifunctional properties in regulation of animal physiological and defense responses, we interpret that amphibian IFNs may evolve novel function pertinent to their superior molecular diversity. Such new function revealed by the emerging studies about antifungal and developmental regulation of amphibian IFNs will certainly promote our understanding of immune evolution in vertebrates to address current pathogenic threats causing amphibian decline.

Highlights

Schematic(IFN) evolution evolution and and recent recent discovery discovery about about amphibian amphibian
Several recent studies have revealed previously unknown complexity of the amphibian interferon (IFN) system
Interferon (IFN)-mediated immune response involves IFNs and several hundreds of IFN-stimulated genes (ISGs) that play a pivotal role in antiviral defense [4,5,6,7]

Summary

Schematic

(IFN) evolution evolution and and recent recent discovery discovery about about amphibian amphibian. Are amphibians unique for the study of the signature event of IFN evolution that leads to antiviral superiority of intronless IFNs in amniotes, but amphibian models are irreplaceable in order to determine the evolutionary coordination and functional diversity among the IFN subgroups [12,13,14,15,16] This is because amphibians represent the only animal clade to have both IFN gene subgroups (intronless vs intron-containing) in either IFN-I or IFN-III types (Table 1 and Figure 1) [12,13,14,15,16]

The Fish-Like Intron-Containing IFN Genes in Amphibians

The Expansion of Amniote-Like Intronless IFN Genes in Amphibians

Phylogenic View and Evolutionary Postulation about Amphibian IFN Evolution

Amphibian IFN Complex

Conclusive Remarks