Saitoh Tetsuroh, Katoh Masaru
Genetics and Cell Biology Section, Genetics Division, National Cancer Center Research Institute, Tokyo 104-0045 Japan.
Int J Mol Med. 2002 Jul;10(1):119-23.
Human ST7R (ST7-like, ST7L) is a paralog of tumor suppressor gene ST7 in the human genome. ST7R gene is clustered with WNT2B gene in human chromosome 1p13, while ST7 gene is clustered with WNT2 gene in human chromosome 7q31. Here, we have cloned mouse ortholog of human ST7R using bioinformatics and cDNA-PCR. Mouse St7r was found to encode 559 amino-acid polypeptide. Mouse St7r showed 90.7% total-amino-acid identity with human ST7R isoform 4 (ST7R4), and 71.6% total-amino-acid identity with human ST7 and mouse St7. Three tyrosine-phosphorylation sites as well as ST7R homologous domains (S7H1, S7H2, and S7H3) were conserved among mouse St7r, human ST7R, mouse St7, and human ST7. Leucine zipper domain of mouse St7r was conserved in human ST7R, but not in mouse St7 and human ST7. Mouse St7r was expressed almost ubiquitously in adult mouse tissues and also in mouse embryos. Although mouse genome draft sequence including mouse St7r gene has not yet been identified, rat genome draft sequence AC106372.1 was found to include rat St7r gene as well as rat Wnt2b gene. These results indicate evolutional conservation of ST7R-WNT2B gene cluster. This is the first report on molecular cloning and initial characterization of mouse St7r.
人类ST7R（类ST7，ST7L）是人类基因组中肿瘤抑制基因ST7的旁系同源基因。ST7R基因与WNT2B基因在人类染色体1p13上成簇，而ST7基因与WNT2基因在人类染色体7q31上成簇。在此，我们利用生物信息学和cDNA-PCR克隆了人类ST7R的小鼠直系同源基因。发现小鼠St7r编码559个氨基酸的多肽。小鼠St7r与人类ST7R亚型4（ST7R4）的总氨基酸同一性为90.7%，与人类ST7和小鼠St7的总氨基酸同一性为71.6%。小鼠St7r、人类ST7R、小鼠St7和人类ST7之间有三个酪氨酸磷酸化位点以及ST7R同源结构域（S7H1、S7H2和S7H3）是保守的。小鼠St7r的亮氨酸拉链结构域在人类ST7R中保守，但在小鼠St7和人类ST7中不保守。小鼠St7r在成年小鼠组织以及小鼠胚胎中几乎普遍表达。虽然尚未鉴定出包括小鼠St7r基因在内的小鼠基因组草图序列，但发现大鼠基因组草图序列AC106372.1包含大鼠St7r基因以及大鼠Wnt2b基因。这些结果表明ST7R-WNT2B基因簇的进化保守性。这是关于小鼠St7r分子克隆和初步表征的首次报道。
