Full Text (PDF)
Our group is primarily interested in the molecular bases of liver cancer and hematopoietic tumors/leukemia. Human cancer development is a multistep process that involves a series of genetic mutations and interactions between different cellular signaling pathways. We are studying the combinatorial effects of oncogenes in tumor development, maintenance, and expansion. So far, no mouse models are available to combine multiple oncogenes in a spatial and timely controlled manner. For this purpose, we are developing a novel mouse model that mimics dynamic gene cascades that are essential for the process of tumorigenesis. Transgenic mice are generated in a way that they express, in an inducible manner, several oncogenes. These genes can be activated by the cre/LoxP system, which results in random combinations of expressed oncogenes. Combinations that provide a growth advantage to cells should be selected, thus, obeying a Darwinian principle for tumor development.
www.lbicr.lbg.ac.at
To study the cooperativity of signaling pathways in tumor development, we generate transgenic mice that harbor three or more inducible genes of interest, each combined with a specific reporter molecule for microscopic detection of expression. For our purposes, we combine all these elements in one bacterial artificial chromosome (BAC), which is used to generate transgenic mice via pronuclear injection, or targeted embryonic stem cells via homologous recombination. As a result, we are deriving large constructs with many repetitive elements. Conventional BAC modification strategies with a number of duplicative elements can result in unwanted recombination events that make the modification process more difficult and time-consuming. To overcome this problem, we designed a strategy that uses ΦC31 integrase-mediated cassette exchange. This way we can insert large, complex, and repetitive DNA molecules up to approximately 25 kb efficiently into a BAC. This allows us to generate transgenic mice expressing up to three genes from the same locus.
See “ΦC31-mediated cassette exchange into a bacterial artificial chromosome” on page 659.
