@article{mbs:/content/journal/micro/10.1099/00221287-148-4-1039, author = "Campoy, Susana and Jara, Mónica and Busquets, Núria and de Rozas, Ana M. Pérez and Badiola, Ignacio and Barbé, Jordi", title = "Intracellular cyclic AMP concentration is decreased in Salmonella typhimurium fur mutantsThe GenBank accession number for the sequence reported in this paper is AF268282.", journal= "Microbiology", year = "2002", volume = "148", number = "4", pages = "1039-1048", doi = "https://doi.org/10.1099/00221287-148-4-1039", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-148-4-1039", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "FURTA, Fur titration assay", keywords = "iron-uptake system", keywords = "cpdA", keywords = "DPD, 2,2-dipyridyl", keywords = "gene regulation", abstract = "It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial species, including Salmonella typhimurium. In this study it has been shown that the intracellular concentration of cyclic AMP (cAMP) is lower in a knockout S. typhimurium fur mutant than in the wild-type strain. According to this, the expression of two cAMP-regulated genes, such as pepE (encoding an α-aspartyl dipeptidase) and the Escherichia coli lac operon, is decreased in S. typhimurium fur cells in comparison with wild-type cells. Introduction of an additional mutation in cpdA, encoding a cyclic 3′,5′-cAMP phosphodiesterase, recovers wild-type intracellular cAMP concentration in the S. typhimurium fur mutant. Likewise, expression of pepE and the E. coli lac operon was the same in the S. typhimurium fur cpdA double mutant and the wild-type strain. Moreover, these results also demonstrate that the S. typhimurium Fur protein positively regulates the expression of the flhD master operon governing the flagellar regulon. This positive control must be mediated by binding of the S. typhimurium Fur protein to the flhD promoter as indicated by the fact that this promoter tests positive in a Fur titration assay.", }