Cloning of Interleukin-10 from African Clawed Frog (Xenopus tropicalis), with the Finding of IL-19/20 Homologue in the IL-10 Locus

• Main Authors: Zhitao Qi, Qihuan Zhang, Zisheng Wang, Weihong Zhao, Qian Gao
• Format: Article
• Language: English
• Published: Hindawi Limited 2015-01-01
• Series: Journal of Immunology Research
• Online Access: http://dx.doi.org/10.1155/2015/462138

Interleukin-10 (IL-10) is a pleiotropic cytokine that plays an important role in immune system. In the present study, the IL-10 gene of African clawed frog (Xenopus tropicalis) was first cloned, and its expression pattern and 3D structure were also analyzed. The frog IL-10 mRNA encoded 172 amino acids which possessed several conserved features found in IL-10s from other species, including five-exon/four-intron genomic structure, conserved four cysteine residues, IL-10 family motif, and six α-helices. Real-time PCR showed that frog IL-10 mRNA was ubiquitous expressed in all examined tissues, highly in some immune related tissues including kidney, spleen, and intestine and lowly in heart, stomach, and liver. The frog IL-10 mRNA was upregulated at 24 h after LPS stimulation, indicating that it plays a part in the host immune response to bacterial infection. Another IL, termed as IL-20, was identified from the frog IL-10 locus, which might be the homologue of mammalian IL-19/20 according to the analysis results of the phylogenetic tree and the sequence identities.