Identification of alternatively spliced isoforms of interleukin-2/15 receptor beta chain in ducks

Abstract

Interleukin (IL)-2 and IL-15 receptor 13 (IL-2/15R beta, CD122) play important roles in signal transduction for biological functions of IL-2 and IL-15. We found that ducks possess three different IL-2/15R beta transcripts, a conventional form (duIL-2/15R beta) and two variants. Comparisons between the cDNA and genomic sequences revealed that the two variants, duIL-2/15R beta-d7 and duIL-2/15R beta-d9, were novel spliced transcripts resulting from skipping exons 7 and 9, respectively. Expression profiles of duIL-2/15R beta and its isoforms were examined in healthy tissues, concanavalin A (ConA)-stimulated splenic lymphocytes and in livers and spleens of Riemerella anatipestifer-infected ducks using quantitative realtime PCR (qRT-PCR). Generally, duIL-2/15R beta-d9 expression was undetectable in healthy tissues, ConA-activated samples, and R. anatipestifer-infected ducks. Expression levels of duIL-2/15R beta transcript were relatively high to moderate in all healthy tissues tested, while duIL-2/15R13-d7 expression was low. Compared to untreated controls, expression levels of duIL-2/15R beta were elevated in ConA-activated splenic lymphocytes and in livers on day 7 in R. anatipestifer-infected ducks, while duIL-2/15R beta-d7 expression was unchanged. Additionally, COS-7 cells transfected with duIL-2/15R beta, duIL-2/15R beta-d7, or duIL-2/15R beta-d9 constructs generated 73 kilodalton (kDa), 31 kDa, and 40 kDa proteins, respectively. This study identified three different IL-2/15R beta transcripts, including two isoforms generated by alternative splicing and their gene expression patterns in stimulated conditions. (C) 2014 Elsevier B.V. All rights reserved.