Identification of multiple sites in the promoter region of the Tetrahymena pyriformis rRNA gene which bind the Escherichia coli catabolite regulatory protein

The base sequence of the Tetrahymena pyriformis rRNA gene transcription initiation region has been reported (Niles, E.G., Sutiphong, J., and Haque, S. (1981) J. Biol. Chem. 256, 12849-12856). Upstream from the transcription initiation point, a collection of three families of highly conserved repeated sequences were identified, which may play a role in the expression of this gene. One of these families, repeat II, which has 10 members repeated in tandem, was recently observed to be strikingly similar in sequence to the Escherichia coli catabolite regulatory protein recognition site. In order to determine if these sequences can serve as catabolite regulatory protein binding sites, direct binding experiments were undertaken using a combination of the gel electrophoretic mobility alteration assay (Fried, M.G., and Crothers, D.M. (1983) Nucleic Acids Res. 11, 141-158) and DNA footprinting. DNA sequence-specific and cyclic AMP-dependent binding of catabolite regulatory protein to several of the apparent recognition sites has been demonstrated.