Isolation, identification and expression analysis of interleukin 2 receptor alpha chain (CD25) gene in Tupaia belangeri

CD25 is an important cell surface marker for CD4+CD25+ regulatory T cells (Tregs) and tree shrew is an animal model used in the study of human viral infections. However, the molecular identity of tree shrew CD25 (tsCD25) remains unclear. We cloned tsCD25 and analyzed its expression pattern. A full-length cDNA of tree shrew interleukin 2 receptor alpha chain(tsCD25) gene was obtained from tree shrew spleen by RT-PCR (reverse transcription-polymerase chain reaction). The tsCD25 cDNA contains an ORF of 816 bp, encoding a 309 ku of peptide with a predicted 271 amino acids. The mature tsCD25 peptide contains two Sushi domains, two N-linked and multiple O-linked glycosylation sites. The tsCD25 is very similar to those of primates at the amino acid level, ranging from 653% to 664%. Tissue transcription analysis indicates that tsCD25 mRNA is expressed in peripheral blood, spleen and lung. Lymphocytes expression analysis demonstrates that tsCD25 mRNA is up-regulated by PMA and ionomycin stimulation. Our results may provide a basis for future studies such as generating monoclonal antibodies to tsCD25.