Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-52670
Dev Comp Immunol January 1, 2017; 67 166-176.

Intronless and intron-containing type I IFN genes coexist in amphibian Xenopus tropicalis: Insights into the origin and evolution of type I IFNs in vertebrates.

Gan Z , Chen SN , Huang B , Hou J , Nie P .


Abstract
Type I IFNs are considered to be the core IFN species in vertebrates because of their predominant antiviral effects. But, a puzzling question remains to be answered, as to how intronless type I IFN genes in amniotes might have evolved from intron-containing type I IFN genes in fish and amphibians. In this study, intronless and intron-containing type I IFNs were found in the amphibian model, Xenopus tropicalis, with a total of sixteen and five genes, respectively. The intronless IFNs can be divided into three subgroups, and the intron-containing ones into two subgroups, implying that a retroposition event might have occurred in amphibians, resulting in the generation of intronless type I IFN genes. Two models were tentatively proposed to explain the evolution of type I IFNs in vertebrates: in model A, fish should possess the most primitive multi-exon-containing type I IFNs, and intronless type I IFN genes in amphibians are the ancestor of modern intronless type I IFNs in amniotes; in model B, intronless type I IFN genes in X. tropicalis may just represent an independent bifurcation in this species or probably in amphibians, and intronless type I IFN genes in amniotes may have arisen from another retroposition event occurred in a transition period even when reptiles were diverged from amphibians. It is considered that the model B can reflect the current knowledge on the occurrence of intronless and intron-containing type I IFN genes in vertebrate lineages. This study thus contributes to a better understanding of the origin and evolution of type I IFNs in vertebrates, and of the occurrence of intronless I IFNs in higher vertebrates.

PubMed ID: 27780747
Article link: Dev Comp Immunol

Genes referenced: cdkn2b focad gcdh hacd4 ifnar1 jak1 lgals9 mtap rab3d stat1 stat2 tyk2



Xenbase: The Xenopus laevis and X. tropicalis resource.
Version: 4.11.1


Major funding for Xenbase is provided by grant P41 HD064556