BBB seminar: James Lorens

James Lorens
Department of Biomedicine, University of Bergen

The generation and analysis of mutant phenotypes in model organisms is a cornerstone of genetics and a powerful approach to elucidating gene function. In less genetically tractable systems, expression of dominant genetic modifiers such as small interfering RNA, cyclic peptides and GFP-fusion proteins can perturb specific cellular interactions. By mimicking mutant alleles, such "perturbagens" can reveal genes relevant for specific biological processes. Retrovirally-mediated functional genetic discovery approaches build on these basic genetic principles. The unique properties of retroviruses make them ideal tools for the introduction of large and diverse libraries of potential genetic effectors into a variety of cell types. Large-scale multi-parametric phenotypic analysis using flow cytometry allows the identification and recovery of intracellular library elements responsible for altered cellular responses, establishing a direct connection between a specific protein and a given phenotypic response. This approach can be successfully applied to study various cell physiologies. I will describe the development of this approach and a novel application to address cellular mechanisms of angiogenesis. Results from functional genetic screens in primary human endothelial cells have revealed several novel regulators of angiogenesis. We demonstrate that changes in the endothelial surface integrin repertoire correlates with angiogenic transitions and that modulating integrin function is an important regulatory strategy of tumor-stroma interactions.