Winnischofer Sheila Maria Brochado, de Oliveira Maria Leonor Sarno, Sogayar Mari Cleide
Instituto de Química-Universidade de São Paulo, CP 26077, 05513-970 São Paulo, Brasil.
J Cell Biochem. 2003 Oct 1;90(2):253-66. doi: 10.1002/jcb.10628.
Polyomavirus (Py) encodes a potent oncogene, the middle T antigen (MT), that induces cell transformation by binding to and activating several cytoplasmic proteins which take part in transduction of growth factors-induced mitogenic signal to the nucleus. We have previously reported that the AP-1 transcriptional complex is a target for MT during cell transformation although, its activation was not sufficient for establishment of the transformed phenotype. Here we show that expression of a dominant-negative cJun mutant in MT transformed cell lines inhibits its transformation ability, indicating that constitutive AP-1 activity is necessary for cell transformation mediated by MT. Evidences also suggest that proliferation of MT transformed cells in low serum concentrations and their ability to form colonies in agarose are controlled by distinct mechanisms.
多瘤病毒（Py）编码一种强效癌基因——中T抗原（MT），该抗原通过结合并激活几种细胞质蛋白来诱导细胞转化，这些细胞质蛋白参与将生长因子诱导的有丝分裂信号转导至细胞核。我们之前曾报道，AP-1转录复合体是细胞转化过程中MT的作用靶点，不过，其激活并不足以确立转化表型。在此我们表明，在MT转化的细胞系中表达显性负性cJun突变体可抑制其转化能力，这表明组成型AP-1活性是MT介导的细胞转化所必需的。证据还表明，MT转化细胞在低血清浓度下的增殖及其在琼脂糖中形成集落的能力受不同机制控制。
