Identification of the genes for human diseases by the nucleotide analyses in wide range and developing the model mouse for them

基于我们之前的成果，HLA区域（跨越1.8 Mb）位于6p21的短臂上。人类6号染色体中的3号基因已经进行了高精度的测序，我们试图确定两种人类疾病（Bechet病[BA]和牛皮癣-[PA]）的候选基因，并建立这两种疾病的动物模型。以下是我们在过去三年中所取得的成绩。遗传分析表明，负责PA的区域位于HLA-C位点端粒侧89 ~ 143kb的区域内。在该区域，有1个已知基因和4个新基因在皮肤中表达。该区域的测序结果显示，4个新基因中有一个表现出显著的多态性。该基因被命名为“SEEK1”，在患有pa2的皮肤中过度表达。对于双相障碍的候选基因，HLA-B基因本身或其邻近的MICA或MICB基因被认为是最佳候选基因。然而，最近的基因分析显示，HLA-B51基因是导致BD.3的基因。我们生产了几个转基因（Tg）系，携带含有SEEK1基因的30kb片段。对这些线路的进一步分析正在进行中。在确定HLA-B51基因是BD的致病基因之前，我们已经生产了携带MICA或MICB基因的Tg系。这些MICA或MICB Tg系表现出一些异常，如白细胞数量和体重减少，皮肤角化过度，提示这些基因可能参与BD的发病机制。我们还生产了携带HLA-B51和人b2微球蛋白基因的Tg系，发现在这些小鼠中，细胞表面HLA-B51分子的表达大大升高。目前，利用敲除b2m基因的小鼠成功地培育出了携带人类b2-微球蛋白（b2m）和HLA-B51基因但缺乏小鼠b2m基因的小鼠。

Based on our previous achievement that HLA region (spanning 1.8 Mb) positioned at the short arm of 6p21. 3 in the human chromosome 6 has already been sequenced with high accuracy, we attempted to identify candidate genes responsible for two human diseases (Bechet's disease [BA] and Psoriasis-[PA]) and create animal models for these two diseases. The following is the achievement we have performed in the past three years.1. A region responsible for PA was confined to a region spanning 89 to 143 kb from the telomere side of HLA-C locus by genetic analyses. In this region, there were one known and 4 novel genes expressed in a skin. Sequencing of this region revealed that one of the 4 novel gene exhibited a significant polymorphism. This gene was termed "SEEK1" and found to overexpress in the skin suffered with PA.2. For the candidate gene for BD, HLA-B gene itself or its neiboring MICA or MICB gene has been considered for the best candidate. However, recent genetic analysis revealed that HLA-B51 gene is the responsible gene for BD.3. We produced several transgenic (Tg) lines carrying a 30-kb fragment containing SEEK1 gene. Further analysis of these lines is now underway.4. We have already produced Tg lines carrying MICA or MICB gene, just prior to decision that HLA-B51 gene is the responsible gene for BD. These MICA or MICB Tg lines exhibited several abnormalities such as reduction in the nubmer of leukocytes and body weight, and hyperkeratosis in the skin, suggesting possible involvement of these genes in the pathogenesis of BD.5. We also produced Tg lines carrying HLA-B51 and human b2-microglobulin genes and found that in these mice expression of HLA-B51 molecules on the cell surface was greatly elevated. Mice carrying human b2-microglobulin (b2m) and HLA-B51 genes, but lacking mouse b2m gene are now successfully produced using b2m-knock out mice.