2 research outputs found
Two copies of the genes encoding the subunits of putative interleukin (IL)-4/IL-13 receptors, IL-4RĪ±, IL-13RĪ±1 and IL-13RĪ±2, have been identified in rainbow trout (Oncorhynchus mykiss) and have complex patterns of expression and modulation
Abstract Mammalian interleukin-4 (IL-4) and IL-13 are T
helper type 2 (Th2) cytokines with pleiotropic functions in
immunity. They signal through receptors containing
IL-4RĪ± and IL-2RĪ³ or IL-13RĪ±1. In addition, a decoy
receptor, IL-13RĪ±2, is known to exist and modulates the
function of IL-13. The existence of fish orthologues to
mammalian IL-4 and IL-13 is still under debate. However,
the receptor chains have been predicted in zebrafish, and
we have previously cloned IL-2RĪ³ and IL-13RĪ±2 in
rainbow trout. In this study, we have cloned a further five
novel trout IL-4/13 receptors. Thus, each of the IL-4RĪ±,
IL-13RĪ±1 and IL-13RĪ±2 chains has two copies. The
identities of the receptors is supported by homology
analysis, characteristic domain structure, phylogenetic tree
analysis and synteny analysis in zebrafish. However, the
characteristic WSXWS motif of structural importance in
mammalian type I cytokine receptors is missing in all fish
IL-4RĪ± and IL-13RĪ±1 molecules. All the receptors have a
characteristic domain structure that is similar to their
mammalian counterparts except for IL-13RĪ±1b that has
the N-terminal Ig domain missing. Since this Ig domain is a
specific and critical binding unit for IL-13 but not for IL-4
signalling, its absence potentially converts the IL-13RĪ±1b
into a receptor that can only signal via IL-4 ligation. The
existence of duplicated receptor genes perhaps suggests that
more ligands still remain to be discovered that will bind
these receptors. The duplicated receptors are differentially
expressed in most tissues and cell lines examined, and their
expression can be modulated by LPS, polyIC and IFN-Ī³ in
cell lines. In contrast, the T-cell stimulant phytohaemagglutinin
increased the expression of IL-4RĪ±1 and IL-4RĪ±2,
but not IL-13RĪ±1/2, suggesting a role of an IL-4-like
molecule in T-cell growth/activation in fish.Peer reviewe
Two copies of the genes encoding the subunits of putative interleukin (IL)-4/IL-13 receptors, IL-4RĪ±, IL-13RĪ±1 and IL-13RĪ±2, have been identified in rainbow trout (Oncorhynchus mykiss) and have complex patterns of expression and modulation
Abstract Mammalian interleukin-4 (IL-4) and IL-13 are T
helper type 2 (Th2) cytokines with pleiotropic functions in
immunity. They signal through receptors containing
IL-4RĪ± and IL-2RĪ³ or IL-13RĪ±1. In addition, a decoy
receptor, IL-13RĪ±2, is known to exist and modulates the
function of IL-13. The existence of fish orthologues to
mammalian IL-4 and IL-13 is still under debate. However,
the receptor chains have been predicted in zebrafish, and
we have previously cloned IL-2RĪ³ and IL-13RĪ±2 in
rainbow trout. In this study, we have cloned a further five
novel trout IL-4/13 receptors. Thus, each of the IL-4RĪ±,
IL-13RĪ±1 and IL-13RĪ±2 chains has two copies. The
identities of the receptors is supported by homology
analysis, characteristic domain structure, phylogenetic tree
analysis and synteny analysis in zebrafish. However, the
characteristic WSXWS motif of structural importance in
mammalian type I cytokine receptors is missing in all fish
IL-4RĪ± and IL-13RĪ±1 molecules. All the receptors have a
characteristic domain structure that is similar to their
mammalian counterparts except for IL-13RĪ±1b that has
the N-terminal Ig domain missing. Since this Ig domain is a
specific and critical binding unit for IL-13 but not for IL-4
signalling, its absence potentially converts the IL-13RĪ±1b
into a receptor that can only signal via IL-4 ligation. The
existence of duplicated receptor genes perhaps suggests that
more ligands still remain to be discovered that will bind
these receptors. The duplicated receptors are differentially
expressed in most tissues and cell lines examined, and their
expression can be modulated by LPS, polyIC and IFN-Ī³ in
cell lines. In contrast, the T-cell stimulant phytohaemagglutinin
increased the expression of IL-4RĪ±1 and IL-4RĪ±2,
but not IL-13RĪ±1/2, suggesting a role of an IL-4-like
molecule in T-cell growth/activation in fish.Peer reviewe