Molecular identification of duck and quail common cytokine receptor γ chain genes

Common cytokine receptor gamma chain (gamma(c)) family cytokines play crucial roles in the regulation of innate and adaptive immune responses. Unlike mammals, chickens possess two different gamma(c) transcripts. To determine if this difference is present in other avian species, gamma(c) cDNA and genomic clones from ducks and quails were investigated. Two different gamma(c) transcripts were identified in both species and designated as duck gamma(c)-a (du gamma(c)-a), du gamma(c)-b, quail gamma(c)-a (qu gamma(c)-a), and qu gamma(c)-b. Comparisons between the duck and quail gamma(c) cDNA and genomic sequences indicated that the two transcripts were produced by alternative splicing. Unexpectedly, the du gamma(c)-b contained the fifth intron, a frame-switching 88-bp insertion, resulting in a receptor molecule lacking a transmembrane region. These findings indicate a possibility that avian species, unlike mammals, express two different gamma(c) transcripts due to alternative splicing. This study is the first demonstration of an alternatively spliced gamma(c) isoform that lacks a transmembrane domain. (C) 2010 Elsevier B.V. All rights reserved.