Expression and characterization of a constitutively active STAT6 from Tetraodon.
In this paper, we report the cloning and characterization of the STAT6 gene from the pufferfish, Tetraodon nigroviridis. The TnSTAT6 gene is composed of 20 exons and 19 introns. The exon-intron organization of this gene is similar to that of HsSTAT6 except for the exons encoding the C-terminal transactivation domain. The full-length complementary (c)DNA of TnSTAT6 encodes a 794-amino acid protein that is 31% identical to human STAT6. We generated a constitutively active TnSTAT6-JH1 by fusing the kinase domain of carp JAK1 to the C-terminal end of TnSTAT6 and demonstrated that the fusion protein has specific DNA-binding ability and can activate a reporter construct carrying multiple copies of mammalian IL-4-response elements. Interestingly, TnSTAT6-JH1 associated with and phosphorylated TnSTAT6 on Tyr661. Mutation of this residue, Y661W, in TnSTAT6 abolished its association with TnSTAT6-JH1. This is consistent with the importance of the corresponding Tyr641 of HsSTAT6 in tyrosine phosphorylation and dimer formation. On the other hand, treatment of mammalian IL-4 did not induce tyrosine phosphorylation of wild-type TnSTAT6, suggesting that both the divergent N-terminal domain and coiled-coiled domain of TnSTAT6 may affect the interaction of TnSTAT6 with mammalian IL-4 receptor complexes.
Sung
Shu-Chiun
SC
Institute of Biological Chemistry, Academia Sinica, 128 Academia Rd., Sec. 2, Taipei 115, Taiwan, ROC.
Cheng
Chia-Hsiung
CH
Chou
Chih-Ming
CM
Chu
Cheng-Ying
CY
Chen
Gen-Der
GD
Hwang
Pung-Pung
PP
Huang
Fore-Lien
FL
Huang
Chang-Jen
CJ
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D023061:Gene Order; D015847:Interleukin-4 / Q000494:pharmacology; D008969:Molecular Sequence Data; D010766:Phosphorylation; D050800:STAT6 Transcription Factor / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D023721:Tetraodontiformes / Q000235:genetics* / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D018076:DNA, Complementary; D050800:STAT6 Transcription Factor; D015847:Interleukin-4; D014443:Tyrosine