Diverse interleukin-7 mRNA transcripts in Chinese tree shrew (Tupaia belangeri chinensis)

PLoS One. 2014 Jun 19;9(6):e99859. doi: 10.1371/journal.pone.0099859. eCollection 2014.


Interleukin-7 (IL7) is a pleiotropic cytokine that is actively involved in the immune system. The Chinese tree shrew (Tupaia belangeri chinensis) has been proposed as an alternative experimental animal to primates in biomedical research. However, there is a lack of biological knowledge about the immune system of the tree shrew. In this study, we cloned the IL7 gene (tIL7) in the Chinese tree shrew and quantified the expression of mRNA transcripts in eight tissues (heart, liver, spleen, lung, kidney, intestine, skeletal muscle and brain) from 20 individuals. Eleven tIL7 mRNA transcripts were identified in different tissues. The canonical form (tIL7c) had a length of 1817 bp and encoded a predicted gene product with 177 amino acids. Phylogenetic analyses based on the amino acid sequences revealed a considerably large genetic difference between tree shrew and human. Quantification of mRNA expression of transcripts tIL7c, tIL7-sv1, tIL7-sv2 and tIL7-sv3 showed that these transcripts were expressed in all tissues, albeit the expression levels varied in different tissues. Transcripts tIL7c, tIL7-sv1, and tIL7-sv2 had the lowest expression in brain, and tIL7-sv3 had a dramatically high mRNA expression in skeletal muscle and heart. The mRNA expression levels of tIL7c and tIL7-sv1 were significantly increased upon ploy(I:C) stimulation in tree shrew primary renal cells. As with human full-length IL7, tIL7c, tIL7-sv1, tIL7-sv2 and tIL7-sv3 showed similar a subcellular localization pattern. Our results identified diverse tIL7 transcripts in the Chinese tree shrew, which may play a potential role in modulating IL7-regulated biological effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Brain / immunology
  • Brain / metabolism
  • Cloning, Molecular
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / immunology
  • Gene Expression
  • HeLa Cells
  • Humans
  • Interleukin-7 / genetics*
  • Interleukin-7 / immunology
  • Kidney / cytology
  • Kidney / immunology
  • Kidney / metabolism
  • Molecular Sequence Data
  • Muscle, Skeletal / immunology
  • Muscle, Skeletal / metabolism
  • Myocardium / immunology
  • Myocardium / metabolism
  • Open Reading Frames
  • Organ Specificity
  • Phylogeny
  • Poly I-C / pharmacology
  • Primary Cell Culture
  • Protein Isoforms / genetics
  • Protein Isoforms / immunology
  • RNA, Messenger / genetics*
  • RNA, Messenger / immunology
  • Sequence Alignment
  • Tupaia / genetics*
  • Tupaia / immunology


  • Interleukin-7
  • Protein Isoforms
  • RNA, Messenger
  • Poly I-C

Grant support

This study was supported by the National 863 Project of China (2012AA021801 and 2012AA022402) and grants from Chinese Academy of Sciences (KSCX2-EW-R-11, KSCX2-EW-J23 and One-Three-Five Strategic Planning Project) and Yunnan Province (2013FB071). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.