Complete genomic organization and promoter analysis of the round-spotted pufferfish JAK1, JAK2, JAK3, and TYK2 genes

We have previously reported the isolation of the JAK1 gene from the round-s potted pufferfish, In the present study, nle cloned and characterized genom ic sequences encoding pufferfish JAK2, JAK3, and TYK2, which are other memb ers of JAK family, To our knowledge, this is the first report to demonstrat e the existence of four JAK genes in fish. All pufferfish JAK genes except JAK1 are composed of 24 exons; JAK1 has an additional exon, A comparison of the exon-intron organization of these genes revealed that the splice sites of JAK genes are nearly identical. In addition, all pufferfish JAK genes h ave one intron in the 5' untranslated region. Taken together, these data su ggest that the pufferfish JAK genes may have evolved from a common ancestor . By 5' rapid amplification of cDNA ends and sequence analysis, me deduced the promoter regions for all JAK genes and found they do not contain typica l TATA or CCAAT boxes but rather numerous other potential binding sites for transcription factors. Interestingly, the TYK2 gene is linked to CDC37 in a head-to-tail manner with a small intergenic region of 292 bp, Within this region, there are two potential binding sites for transcriptional factors such as c-Myb and NF-IL6, The putative promoter regions of all JAK genes we re tested either in a carp CF cell line or in zebrafish embryos using CAT o r lacZ as reporter genes. Both assays confirmed the transcriptional activit ies of these promoters in vitro and in vivo.