Transcription factor-promoter interaction networks

The pattern of genome transcription in Escherichia coli determined by controlling the distribution of a total of about 2,000 molecules of RNA polymerase, the transcriptase, among 4,000 genes on its genome. In response to environmental changes, the gene selectivity of the RNA polymerase is modulated after interaction with one sigma subunit, the promoter recognition subunit, in the first step and one or two of about 300 transcription factors in the second step. In order to get insights into the molecular mechanisms underlying the global regulation of genome expression, we have initiated a systematic study of the identification of genes under the control of each transcription factor using the newly developed ´Genomic SELEX´ system. The gene regulation predicted by the Genomic SELEX is being examined by analysis of the promoter activity in the presence and absence of test transcription factors using the newly constructed two-fluorescent-protein promoter assay vector pGRP. Results altogether indicate the involvement of complex networks between transcription factors and promoters in the global regulation of genome transcription