Marsupials are a group of mammals that give birth to relatively underdeveloped young after a short period of gestation, and go on to raise these offspring during an extended period of fixed lactation in a pouch environment. Currently, there is relatively little information available about the marsupial immune system, and in this context, we aimed to isolate and characterise the full length expressed Interleukin-6 gene sequence from three marsupial species; the gray short-tailed opossum (Monodelphis domestica) from the Didelphidae family, as well as the red-tailed phascogale (Phascogale calura) and the kultarr (Antechinomys laniger) from the family Dasyuridae. Interleukin-6 (IL-6) is a pleiotropic cytokine that plays an important role in the immune system of vertebrate animals. It is a pro-inflammatory cytokine and recently has also been described as pro-tumourigenic, as it is implicated in the progression of a number of cancers, and high levels of IL-6 expression are generally predictive of a poor outcome.
Using marsupial-specific consensus primers, fragments of the expressed sequence were identified in all three marsupial species and species-specific primers were then used in RACE PCR to identify the 3' and 5' ends, as well as untranslated regions where possible. These novel sequences were further analysed using bioinformatic techniques to compare IL-6 sequences across all vertebrate species. The key findings of this work will be presented, highlighting marsupial-specific findings as well as the differences between IL-6 isolated from the evolutionary distant Didelphidae and Dasyuridae marsupial groups. The potential for therapeutic IL-6 targeting in marsupial cancers will be discussed, with particular reference to dasyurid marsupials, which have been reported to have a natural susceptibility to developing cancers.