This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Polayes, D A Articles by Dahlberg, J E Search for Related Content PubMed PubMed Citation Articles by Polayes, D A Articles by Dahlberg, J E

research-article

Cyclic AMP-cyclic AMP receptor protein as a repressor of transcription of the spf gene of Escherichia coli.

Department of Physiological Chemistry, University of Wisconsin, Madison 53706.

ABSTRACT

The spf gene of Escherichia coli encodes an unstable 109-nucleotide RNA, spot 42 RNA; the level of this RNA was reduced three- to fivefold when cells were grown in the presence of 3',5'-cyclic AMP (cAMP). We show that this regulation occurs through reduction in transcription and depends on both cAMP and the cAMP receptor protein (CRP) but is independent of the de novo protein synthesis. Through deletion analysis of the spf gene promoter, we have identified sequences that are important in the synthesis of spot 42 RNA. Deletion of sequences upstream of -77 completely eliminated the negative control of cAMP-CRP and resulted in high constitutive levels of transcription. This region contained a sequence that both conformed to the consensus binding site for cAMP-CRP in positively regulated promoters and acted as a cAMP-CRP binding site in a gel retardation assay. Deletion of sequences between positions -77 and -60 greatly reduced the level of transcription in the presence or absence of cAMP-CRP, indicating that at least part of this region is a binding site for a positive-acting transcription factor (or RNA polymerase itself). We propose that the proximity of the two sites defined here allows for the negative control of spf gene transcription by cAMP-CRP. In particular, if only one site at a time can be occupied, the binding of cAMP-CRP would interfere with the binding of a transcription factor.

This article has been cited by other articles:

• Moller, T., Franch, T., Udesen, C., Gerdes, K., Valentin-Hansen, P. (2002). Spot 42 RNA mediates discoordinate expression of the E. coli galactose operon. Genes Dev. 16: 1696-1706 [Abstract] [Full Text]