DNA introduced into a cell usually integrates, if at all, at random in the genome. In order for gene targeting to take place, a small vector must scan a huge genome that is packaged in chromatin, identify and bind the target, and engage in strand exchange. This formidable task is likely to be rate limiting. Our goal is to study the process of genome scanning by the vector, to track it from the time of transformation through genome integration and to assist the vector to identify the homologous target. Our tools are particle imaging and tracking, molecular analysis of integration events, and manipulation of the integration process through protein recognition chemistry. Two main approaches will be used to assist homologous integration: first, by protein bridging (proteins that would bind both target and vector), and second by chromatin remodeling. Second, we propose to analyze the connection between chromatin structure and DNA integration. We will analyze how nucleosome positioning affects patterns of DNA integration. In addition, we will stimulate chromatin remodeling in an attempt to facilitate target invasion by the incoming vector. Parallel assays will be built upon fluorescence and genetic markers to correlate between the mode of search and integration per se. The interdisciplinary use of biophysics, genetics, and computational tools opens the prospect to better understand and manipulate the fundamental mechanisms involved in DNA mobility, plant transformation, and gene targeting.