Inference of complex regulatory network for the cell cycle system in Saccharomyces cerevisiae

Recently we developed a graphical chain modeling procedure to infer a network from expression profiles between different stages, according to the natural order. In this study, this procedure was applied to 796 gene expression profiles of cell-cycle related genes, which were experimentally identified to be transcribed among five cell-cycle phases. These phases were well characterized by the inferred network. In the G1 and S phases, almost all of the genes were related among them, even though limited numbers of genes were related to each other in the other phases. Furthermore, the inferred network indicated that some genes in the former phases have long-distance regulation throughout the cell cycle; however, the main regulatory system in the cell cycle occurred step by step in a manner. This approach provides us a comprehensive analysis of serial gene regulation in the cell cycle system.