Leu J H, Yan S J, Lee T F, Chou C M, Chen S T, Hwang P P, Chou C K, Huang C J
Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
DNA Cell Biol. 2000 Jul;19(7):431-46. doi: 10.1089/10445490050085924.
We have previously reported the isolation of the JAK1 gene from the round-spotted pufferfish. In the present study, we cloned and characterized genomic sequences encoding pufferfish JAK2, JAK3, and TYK2, which are other members of JAK family. To our knowledge, this is the first report to demonstrate 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 have one intron in the 5' untranslated region. Taken together, these data suggest that the pufferfish JAK genes may have evolved from a common ancestor. By 5' rapid amplification of cDNA ends and sequence analysis, we deduced the promoter regions for all JAK genes and found they do not contain typical 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 were tested either in a carp CF cell line or in zebrafish embryos using CAT or lacZ as reporter genes. Both assays confirmed the transcriptional activities of these promoters in vitro and in vivo.
我们之前曾报道过从圆点河豚中分离出JAK1基因。在本研究中，我们克隆并鉴定了编码河豚JAK2、JAK3和TYK2的基因组序列，它们是JAK家族的其他成员。据我们所知，这是首次报道鱼类中存在四种JAK基因。除JAK1外，所有河豚JAK基因均由24个外显子组成；JAK1有一个额外的外显子。对这些基因的外显子-内含子组织进行比较发现，JAK基因的剪接位点几乎相同。此外，所有河豚JAK基因在5'非翻译区都有一个内含子。综上所述，这些数据表明河豚JAK基因可能起源于一个共同的祖先。通过5' cDNA末端快速扩增和序列分析，我们推断出所有JAK基因的启动子区域，发现它们不包含典型的TATA或CCAAT框，而是含有许多其他潜在的转录因子结合位点。有趣的是，TYK2基因与CDC37以头对头的方式相连，中间有一个292 bp的小基因间隔区。在这个区域内，有两个潜在的转录因子结合位点，如c-Myb和NF-IL6。使用CAT或lacZ作为报告基因，在鲤鱼CF细胞系或斑马鱼胚胎中对所有JAK基因的推定启动子区域进行了测试。两种检测方法都证实了这些启动子在体外和体内的转录活性。
