RRC ID 53564
Author Nakano M, Ogasawara H, Shimada T, Yamamoto K, Ishihama A.
Title Involvement of cAMP-CRP in transcription activation and repression of the pck gene encoding PEP carboxykinase, the key enzyme of gluconeogenesis.
Journal FEMS Microbiol Lett
Abstract cAMP receptor protein (CRP) is the best characterized global regulator of Escherichia coli. After genomic SELEX screening, a total of minimum 378 promoters have been identified as its regulation targets on the E. coli genome. Among a number of promoters carrying two CRP-binding sites, several promoters carry two CRP-binding sites, one upstream but another downstream of transcription initiation sites. The regulatory role of downstream CRP site remains unsolved. Using the pck gene encoding phosphoenolpyruvate carboxykinase as a model promoter, we analyzed the role of CRP-associated downstream of the transcription initiation site. Gel shift assay and AFM observation indicate that CRP binds to both the promoter-distal site (CRP box-1) at -90.5 and the site (CRP box-2) at +13.5 downstream of transcription initiation site. The binding affinity is higher for CRP box-1. Roles of two CRP sites were examined using in vitro transcription assay and in vivo reporter assay. In both cases, transcription repression was observed in the presence of high concentrations of CRP. Taken together, we propose that cAMP-CRP associated at downstream CRP box-2 plays as a repressor for pck transcription only in the presence of high levels of cAMP-CRP.
Volume 355(2)
Pages 93-9
Published 2014-6-1
DOI 10.1111/1574-6968.12466
PMID 24814025
MeSH Cyclic AMP Receptor Protein / genetics Cyclic AMP Receptor Protein / metabolism* Epigenetic Repression / genetics* Escherichia coli / enzymology Escherichia coli / genetics* Gene Expression Regulation, Bacterial Genes, Bacterial Genetic Testing Gluconeogenesis / genetics* Microscopy, Atomic Force Phosphoenolpyruvate Carboxykinase (ATP) / genetics* Promoter Regions, Genetic Transcriptional Activation*
IF 1.987
Times Cited 11
Prokaryotes E. coli