Cloning of interleukin-10 from african clawed frog (Xenopus tropicalis),with the finding of IL-19/20 homologue in the IL-10 locus

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. © 2015 zhitao qi et al.