We plan to conduct structural biology studies to unravel action mechanisms of cellular macromolecular systems comprising DNAs, RNAs, and proteins, typified by various complexes of RNA polymerases bound with nucleic acids and transcription factors. To this end, we will develop a technology platform for the supramolecular structure analysis, with novel methods for the preparation of biologically significant macromolecular complexes consisting of a number of large components and for the structure analysis by taking advantage of SPring-8/SACLA and other spectroscopic methods.