Regulation Of Transgene Expression

我们实验室的研究目标是更深入地了解化学物质或环境损害引发的致瘤过程中的分子机制。为了实现这一目标，我们开发了一种名为Tg.AC的转基因小鼠系。Tg。AC小鼠被改造成含有v-Ha-ras癌基因，其功能已被发现与人类大多数上皮肿瘤相关或导致。Tg。AC转基因小鼠在受伤、局部用化学致癌物治疗或暴露于紫外线辐射时产生皮肤乳头瘤。当用非致癌物治疗时，它们不会产生肿瘤。由于这种独特的表型，Tg。美国国家毒理学计划（NTP）正在对AC小鼠模型进行评估，以作为传统的两年生物测定法的辅助手段，以确定致癌物。为了帮助这种评价，我们开发了对Tg育种者进行基因分型的方法。交流鼠标，以确保响应性。此外，我们已经分子表征了转基因在致瘤反应中的作用。为了了解基因表达的调控，我们绘制了启动子和潜在转录因子及其结合位点。我们克隆并测序了小鼠11号染色体上的整合位点。我们实验室最近的数据表明，转基因被整合到一个新的基因中。我们已经确定了这个基因，并正在研究它在调控转基因中可能具有的表达和调控作用。我们也在研究Tg的ras依赖性致瘤反应。在遗传方法中试图了解交流小鼠肿瘤发生的重要信号通路。我们发现小鼠缺乏KSR （Ras激酶抑制因子），这是EGFr介导的信号传导所需的基因产物。当KSR缺陷小鼠与Tg杂交时。AC小鼠TPA依赖性致瘤反应被阻断。这些数据表明EGFr/ras/KSR信号通路在Tg中非常重要。AC肿瘤发生。最后，我们继续使用基因阵列技术来鉴定在ras介导的肿瘤发生中起重要作用的新基因。

Our laboratory's research goal is to gain greater understanding of the molecular mechanisms that function during the tumorigenic process initiated by chemicals or environmental insults. To accomplish this goal we have exploited a transgenic mouse line called Tg.AC. Tg.AC mice were engineered to contain a v-Ha-ras oncogene, whose function has been found to be associated or causal of a majority of epithelial tumors in humans. Tg.AC transgenic mice produce skin papillomas when wounded, topically treated with chemical carcinogens, or exposed to ultraviolet radiation. They do not produce tumors when treated with non-carcinogens. As a result of this unique phenotype, the Tg.AC mouse model is being evaluated by the National Toxicology Program (NTP) as an adjunct to the conventional two-year bioassay for the identification of carcinogens. To aid in this evaluation we have developed assays to genotype the breeders of Tg.AC mice to ensure responsiveness. In addition, we have molecularly characterized the transgene's role in the tumorigenic response. To understand the regulation of gene expression we have mapped the promoter and potential transcription factors and their binding sites. We have cloned and sequenced the integration site on mouse chromosome 11. Recent data from our laboratory indicate that the transgene is integrated in a novel gene. We have identified this gene and are investigating the expression and regulatory role it may have in regulating of the transgene. We are also exploiting the ras dependent tumorigenic response of Tg.AC mice in genetic approaches in an attempt to understand the signaling pathways important for tumorigenesis. We have found that mice deficient in KSR (Kinase Suppressor of Ras) , a gene product required for EGFr mediated signaling. When KSR deficient mice are crossed to Tg.AC mice the TPA dependant tumorigenic response is blocked. This data indicate that the EGFr/ras/KSR signaling pathway is very important in Tg.AC tumorigenesis. Lastly, we continue to use the gene array technology to identify new genes that play significant roles ras mediated tumorigenesis.