The interleukin 2 receptor (IL-2R) family of class I cytokine receptors plays important roles in lymphocyte development and function. The mammalian IL-2R family utilize the shared signaling component interleukin 2 receptor gamma common (IL-2Rγc). Mutations of this receptor chain in humans or mice leads to severe combined immunodeficiency (SCID).
The purpose of this project was to examine the IL-2R family in zebrafish and generate a SCID zebrafish model.
Methodologies used include transcription activator-like effector nucleases (TALEN) induced mutagenesis, high resolution melt (HRM) and restriction fragment polymorphism (RFLP) to identify mutants and whole-mount in situ hybridization (WISH) and RT and QRT-PCR for expression analysis. Morpholino mediated knock-down was also used to explore the interleukin 15 receptor (il-15r).
Zebrafish possess 2 paralogues of IL-2Rγc with il-2rγc.a shown to have a conserved role in embryonic T lymphopoiesis. Therefore TALENs were targeted to il-2rγc.a to generate a SCID zebrafish model. Homozygous mutants were immunocompromised and showed reduced T cells at 5 dpf which was also evident at 28 dpf. B cells were expressed at 28 dpf indicating a T-B+ SCID model.
The zebrafish heterotrimeric receptor was also investigated for a conserved role in lymphopoiesis. Zebrafish only possess il-15rα at the il-2rα/il-15rα gene locus resulting in a single ligand specific chain that would signal with interleukin 2 receptor beta (il-2rβ) and il-2rγc.a. The possible complex was investigated by morpholino mediated knockdown of il-15rα, il-2rβ and a possible il-2rβ like and examined for changes in rag1 expression at 5 dpf.