We are working to elucidate the fundamental mechanisms of transcriptional regulation during animal development. Regulatory DNAs called enhancers play a central role in controlling the temporal and spatial specificity of gene expression in response to intrinsic and extrinsic signals. It is estimated that more than 900,000 enhancers are embedded in the human genome, suggesting that a typical human gene is regulated by ~40-50 enhancers. Increasing number of evidence suggests that the diversification of enhancer functions plays a critical role in producing the phenotypic complexities of higher eukaryotes during evolution. However, the fundamental question namely "How do enhancers control transcription dynamics at the molecular level?" remains as an outstanding question in modern biology. Using the early Drosophila embryo as a model, we aim to understand the fundamental principles of enhancer function by utilizing a wide range of techniques, including live-imaging, super-resolution microscopy, genome-editing, biochemistry, and quantitative image analysis.