CRP (cAMP receptor protein), the global regulator of genes for carbon source 
utilization in the absence of glucose, is the best-studied prokaryotic 
transcription factor. A total of 195 target promoters on the Escherichia coli 
genome have been proposed to be under the control of cAMP-bound CRP. Using the 
newly developed Genomic SELEX screening system of transcription factor-binding 
sequences, however, we have identified a total of at least 254 CRP-binding 
sites. Based on their location on the E. coli genome, we predict a total of at 
least 183 novel regulation target operons, altogether with the 195 hitherto 
known targets, reaching to the minimum of 378 promoters as the regulation 
targets of cAMP-CRP. All the promoters selected from the newly identified 
targets and examined by using the lacZ reporter assay were found to be under the 
control of CRP, indicating that the Genomic SELEX screening allowed to identify 
the CRP targets with high accuracy. Based on the functions of novel target 
genes, we conclude that CRP plays a key regulatory role in the whole processes 
from the selective transport of carbon sources, the glycolysis-gluconeogenesis 
switching to the metabolisms downstream of glycolysis, including tricarboxylic 
acid (TCA) cycle, pyruvate dehydrogenase (PDH) pathway and aerobic respiration. 
One unique regulation mode is that a single and the same CRP molecule bound 
within intergenic regions often regulates both of divergently transcribed 
operons.