We use Drosophila embryo as a model to study the dynamic properties of 3D genome organization and the functional significance of chromatin architecture on the regulation of gene transcription. Using a combination of genetics, genome editing and live imaging, we are able to mark specific genes with fluorescent markers and trace the movement of individual loci. Particularly, by simultaneously labeling promoter activity and the position of enhancers, we are able to measure kinetic parameters (e.g. looping probability, dwell time and dissociation constants) for long-range promoter-enhancer interactions. Furthermore, by synthetically tuning the promoter-enhancer distance and the insulator elements that mediate the interactions, we are able to investigate the mechanistic details of chromatin looping and enhancer searching through physical polymer modeling.