Politi Katerina, Szabolcs Matthias, Fisher Peter, Kljuic Ana, Ludwig Thomas, Efstratiadis Argiris
Department of Genetics and Development, Columbia University, New York, New York, USA.
Am J Pathol. 2004 Jan;164(1):325-36. doi: 10.1016/S0002-9440(10)63122-7.
We are using an approach that is based on the cre/loxP recombination process and involves a binary system of Cre-producing and Cre-responding transgenic mice to achieve ubiquitous or tissue-specific expression of oncoproteins. To develop mouse models of tumorigenesis, Cre-producers are mated with responder animals carrying a dormant oncogene targeted into the 3' untranslated region of the locus encoding cytoplasmic beta-actin (actin cassette). Production of oncoprotein from a bicistronic message is accomplished in bitransgenic progeny by Cre-mediated excision of a segment flanked by loxP sites that is located upstream from the oncogenic sequence. Widespread Cre-dependent activation and expression of an actin-cassette transgene encoding the T antigens of the SV40 early region (SVER) commencing in embryos was compatible with normal development and did not impair viability. However, at approximately 3 months of age, all female animals developed massive uterine leiomyosarcomas, whereas practically all males exhibited enormously enlarged seminal vesicles because of pronounced hyperplasia of the smooth muscle layers. In addition, because of smooth muscle hyperproliferation, marked dilation of the gallbladder was observed in mice of both sexes. To begin exploring aberrant signaling events in the SVER-triggered tumorigenic pathways, we analyzed the expression profile of leiomyosarcomas by DNA microarray analysis.
我们正在使用一种基于cre/loxP重组过程的方法，该方法涉及一个由产生Cre的转基因小鼠和对Cre有反应的转基因小鼠组成的二元系统，以实现癌蛋白的全身或组织特异性表达。为了建立肿瘤发生的小鼠模型，将产生Cre的小鼠与携带一个沉默癌基因的反应小鼠进行交配，该癌基因靶向定位到编码细胞质β-肌动蛋白（肌动蛋白盒）的基因座的3'非翻译区。在双转基因后代中，通过Cre介导切除位于致癌序列上游的一段loxP位点侧翼片段，从双顺反子信息中产生癌蛋白。从胚胎期开始，广泛的Cre依赖性激活和表达编码SV40早期区域T抗原（SVER）的肌动蛋白盒转基因与正常发育相容，且不损害生存能力。然而，在大约3个月大时，所有雌性动物都发生了大量子宫平滑肌肉瘤，而几乎所有雄性动物由于平滑肌层明显增生，精囊极度增大。此外，由于平滑肌过度增殖，在两性小鼠中均观察到胆囊明显扩张。为了开始探索SVER触发的致瘤途径中的异常信号事件，我们通过DNA微阵列分析来分析平滑肌肉瘤的表达谱。
