Nikaido T, Shimada K, Nishida Y, Lee R S, Pardee A B, Nishizuka Y
Molecular Biology Unit, Aichi Cancer Center Research Institute, Nagoya, Japan.
Exp Cell Res. 1989 May;182(1):284-9. doi: 10.1016/0014-4827(89)90299-1.
The identification of cellular proteins involved in the control of cell proliferation in normal cells is essential for understanding the mechanism underlying growth regulation and cellular transformation. A nuclear protein termed Ki antigen with a relative mobility of 32,000 (Mr 32K) and which is recognized by SLE patient antisera has been identified in cells of human, bovine, and murine origin. Recently, cDNA clones for the bovine and human Ki antigens have been isolated using SLE patient antisera (T. Nikaido, et al., in preparation). The nucleotide sequence predicted a protein of 239 amino acids with a possible nuclear localization signal resembling that identified in SV40 T antigen and other nuclear proteins. Here we show that the expression of Ki antigen is regulated in the normal cell, but not in the transformed cell. Furthermore, in the K-ras temperature-sensitive mutant cell line, ts 371 normal rat kidney (NRK), Ki antigen expression increases several-fold at the permissive temperature relative to the nonpermissive temperature. These results suggest that expression of Ki antigen might be correlated with cellular transformation as well as with cell growth regulation.
鉴定参与正常细胞中细胞增殖调控的细胞蛋白，对于理解生长调节和细胞转化的潜在机制至关重要。在人、牛和鼠源细胞中已鉴定出一种核蛋白，称为Ki抗原，其相对迁移率为32,000（Mr 32K），可被SLE患者抗血清识别。最近，利用SLE患者抗血清分离出了牛和人Ki抗原的cDNA克隆（T. Nikaido等人，正在准备中）。核苷酸序列预测该蛋白有239个氨基酸，带有一个可能的核定位信号，类似于在SV40 T抗原和其他核蛋白中鉴定出的信号。在此我们表明，Ki抗原的表达在正常细胞中受到调控，但在转化细胞中不受调控。此外，在K-ras温度敏感突变细胞系ts 371正常大鼠肾（NRK）中，相对于非允许温度，在允许温度下Ki抗原表达增加了几倍。这些结果表明，Ki抗原的表达可能与细胞转化以及细胞生长调节相关。
