Two differentially expressed interleukin-11 receptor genes in the mouse genome

Abstract

Interleukin-11 (IL-11) is a multifunctional cytokine involved in the regulation of cell proliferation and differentiation in a variety of cell types and tissues in vitro and in vivo. The effects of IL-11 were shown to be mediated by the IL-11 receptor (hereafter referred to as IL-11Rα), which is a ligand-binding subunit and provides ligand specificity in a functional multimeric signal-transduction complex with gp130. Here we show that the mouse genome contains a second gene encoding an IL-11-binding protein, referred to as IL-11Rβ. The structure of the IL-11Rβ gene is highly similar to that of IL-11Rα, and IL-11Rβ exhibits 99% sequence identity with IL-11Rα at the amino acid level. IL-11Rβ is co-expressed with IL-11Rα, albeit at lower levels, in embryos and in various adult tissues. IL-11Rβ transcripts are abundant in testis, and, in contrast with IL-11Rα, absent from skeletal muscle. IL-11Rβ expressed in vitro binds IL-11 with high affinity, suggesting that the mouse genome contains a second functional IL-11R.