Expression and characterization of the JAK kinase and STAT protein from brine shrimp, Artemia franciscana.
In this study, we isolated and characterized both JAK and STAT genes from Artemia, Artemia franciscana. Although AfJAK showed only 19% identity (33% similarity) to the Drosophila Hop protein, AfJAK contained the characteristic JAK homology domain (JH domain) from JH1 to JH7. On the other hand, AfSTAT showed higher identity (30%) to Drosophila STAT (STAT92E). The low identities of AfJAK and AfSTAT to Drosophila Hop and STAT92E suggest that JAK and STAT proteins are unique in each different species of invertebrate. RT-PCR analysis showed that both AfJAK and AfSTAT transcripts were ubiquitously expressed in the embryo, which is similar to the expression patterns of Drosophila Hop and STAT92E mRNAs during development. In addition, we generated a constitutively active form of AfSTAT by fusing the JH1 domain of AfJAK to the C-terminal end of AfSTAT. This fusion protein, AfSTAT-HA-JH1, autophosphorylated on its tyrosine residue and was able to bind to specific DNA motifs including the STAT-binding motifs in the Drosophila Raf promoter. Both AfJAK and AfSTAT proteins elicited the transactivation potential toward the fly Raf promoter in Sf9 cells. However, tyrosine phosphorylation of AfSTAT was not detected, which is consistent with the cellular localization analysis that most AfSTAT proteins were in the cytoplasm. Our results demonstrate that both JAK and STAT are present in the genome of Artemia, which can serve as the basis for further investigations to explore the role of the JAK/STAT signal pathway in the development and immune response of brine shrimp.
Cheng
Chia-Hsiung
CH
Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan, ROC.
Chen
Gen-Der
GD
Yeh
Maw-Sheng
MS
Chu
Cheng-Ying
CY
Hsu
Ya-Li
YL
Hwang
Pung-Pung
PP
Huang
Fore-Lien
FL
Huang
Chang-Jen
CJ
D000595:Amino Acid Sequence; D000818:Animals; D001156:Artemia / Q000166:cytology / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D053612:Janus Kinases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D050791:STAT Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment
D050791:STAT Transcription Factors; D004247:DNA; D053612:Janus Kinases