Completion of the genome sequence of the model bacterium Escherichia coli has produced nearly 2000 open reading frames (ORFs) that remain to be functionally characterized. To accomplish this goal, we have organized a working project team in Japan and have begun construction of clones containing each of the putative ORFs. The procedure has been conceived such that we shall be able to perform systematic analysis of the shut-off as well as forced expression in vivo of each ORF and purification of its protein product for further biochemical studies. In addition, we have started a collection of various genetic and biochemical data of E. coli published in the past, and analyses of the data from a bio-informatics point of view. Thus, we aim at reaching complete understanding of this model organism in the near future.