Saris C J, Domen J, Berns A
Division of Molecular Genetics, Netherlands Cancer Institute, Amsterdam.
EMBO J. 1991 Mar;10(3):655-64. doi: 10.1002/j.1460-2075.1991.tb07994.x.
The pim-1 gene is frequently found activated by proviral insertion in murine T cell lymphomas. Overexpression of pim-1 in lymphoid cells by transgenesis formally proved its oncogenic potential. The pim-1 cDNA sequence predicts that both murine and human pim-1 encode a 34 kd protein with homology to protein kinases. In this study, we show that the murine pim-1 gene encodes a 44 kd protein in addition to the predicted 34 kd protein. The 44 kd protein is an amino-terminal extension of the 34 kd protein and is synthesized by alternative translation initiation at an upstream CUG codon. Contrary to previous findings by others, we provide evidence that both murine and human pim-1 gene products are protein-serine/threonine kinases. Murine 44 kd and 34 kd pim-1 proteins exhibit comparable in vitro kinase activity and are both mainly cytoplasmic, but they differ in in vivo association state and half-life.
pim-1基因在鼠T细胞淋巴瘤中常因前病毒插入而被激活。通过转基因在淋巴样细胞中过表达pim-1正式证明了其致癌潜能。pim-1 cDNA序列预测，小鼠和人类的pim-1均编码一种与蛋白激酶具有同源性的34kd蛋白。在本研究中，我们发现小鼠pim-1基因除了预测的34kd蛋白外，还编码一种44kd蛋白。44kd蛋白是34kd蛋白的氨基末端延伸产物，由上游CUG密码子处的选择性翻译起始合成。与其他人之前的发现相反，我们提供的证据表明，小鼠和人类的pim-1基因产物都是蛋白丝氨酸/苏氨酸激酶。小鼠44kd和34kd的pim-1蛋白在体外表现出相当的激酶活性，且都主要位于细胞质中，但它们在体内的结合状态和半衰期有所不同。
