MOLECULAR ASPECTS OF COLON EPITHELIUM DIFFERENTIATION AND TUMOR FORMATION

我们已经报道了一个cDNA分离的差异杂交之间 分化和未分化的结肠癌细胞。 小说 转录本科里-1与转录本的5 '非翻译区互补。 krev-1抑癌基因mRNA。 科里-1 mRNA具有开放的阅读框， 编码与大鼠S29核糖体蛋白相同的蛋白。 这 蛋白质具有由四个半胱氨酸组成的潜在锌指基序 残基 为了检测蛋白质的生物学功能， 在E.将大肠杆菌固定在膜上 并在变性后与55Zn孵育。 只有野生型 用55Zn标记，表明这种形式的蛋白质，而不是 突变形式，可以采取锌指构象。 野生型和 将突变的科里-1基因插入表达载体中， 转染到HT1080人纤维肉瘤细胞中。 在ht1080细胞中 转染突变体科里-1，体外和体内细胞生长均受到抑制。 与仅用载体转染的细胞相比增强。 上 另一方面，细胞生长在体外和体内都没有增强， 引入野生型科里-1。 krev-1的表达为 由mRNA或蛋白质决定的蛋白质表达水平， 野生型或突变型科里-1导入HT 1080细胞。 这些结果 提示内源性科里-1的反式显性抑制是由 该基因的突变形式增强了细胞生长和致瘤性， 表型 突变体科里-1的这种功能是由 干扰依赖于锌指结构域的功能， 影响KREV-1表达。

We have reported a cDNA isolated by differential hybridization between differentiated and undifferentiated colon carcinoma cells. The novel transcript, cori-1, is complementary to the 5' untranslated region of the krev-1 anti-oncogene mRNA. Cori-1 mRNA has an open reading frame which encodes a protein identical with the rat S29 ribosomal protein. This protein has a potential zinc finger motif consisting of four cysteine residues. In order to examine the biological function of the protein, mutant cori-1 proteins synthesized in E. coli were fixed on a membrane and incubated with 55Zn after denaturation. Only the wild type was labeled with 55Zn, indicating that this form of the protein, but not the mutant form, may take a zinc finger conformation. The wild type and mutant cori-1 genes were inserted into an expression vector and transfected into HT1080 human fibrosarcoma cells. In HT1080 cells transfected with mutant cori-1, both in vitro and in vivo cell growth was enhanced compared with the cells transfected with vector only. On the other hand, cell growth both in vitro and in vivo was not enhanced when the wild type cori-1 was introduced. The expression of krev-1 as determined by either mRNA or protein was not changed by introducing either wild type or mutant cori-1 into HT1080 cells. These results suggest that the trans-dominant suppression of endogenous cori-1 by the mutant form of the gene enhanced cell growth and the tumorigenic phenotype. This function of the mutant cori-1 is conferred by interfering with a function dependent on the zinc finger domain without affecting krev-1 expression.