title: Metal-responsive promoter DNA compaction by the ferric uptake regulator.
abstract: Short-range DNA looping has been proposed to affect promoter activity in many bacterial species and operator configurations, but only few examples have been experimentally investigated in molecular detail. Here we present evidence for a metal-responsive DNA condensation mechanism controlled by the Helicobacter pylori ferric uptake regulator (Fur), an orthologue of the widespread Fur family of prokaryotic metal-dependent regulators. H. pylori Fur represses the transcription of the essential arsRS acid acclimation operon through iron-responsive oligomerization and DNA compaction, encasing the arsR transcriptional start site in a repressive macromolecular complex. A second metal-dependent regulator NikR functions as nickel-dependent anti-repressor at this promoter, antagonizing the binding of Fur to the operator elements responsible for the DNA condensation. The results allow unifying H. pylori metal ion homeostasis and acid acclimation in a mechanistically coherent model, and demonstrate, for the first time, the existence of a selective metal-responsive DNA compaction mechanism controlling bacterial transcriptional regulation.
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Davide
authors: D
authors: Roncarati
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Simone
authors: S
authors: Pelliciari
authors: Department of Life Sciences, University of Parma, 43124 Parma, Italy.
authors: Nicola
authors: N
authors: Doniselli
authors: Department of Life Sciences, University of Parma, 43124 Parma, Italy.
authors: Stefano
authors: S
authors: Maggi
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Andrea
authors: A
authors: Vannini
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Luca
authors: L
authors: Valzania
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Luca
authors: L
authors: Mazzei
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Barbara
authors: B
authors: Zambelli
authors: Department of Life Sciences, University of Parma, 43124 Parma, Italy.
authors: Claudio
authors: C
authors: Rivetti
authors: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy.
authors: Alberto
authors: 0000-0002-9414-9898
authors: A
authors: Danielli
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D016480:Helicobacter pylori / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D007477:Ions; D007501:Iron / Q000378:metabolism*; D046911:Macromolecular Substances / Q000378:metabolism; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D009698:Nucleoproteins / Q000378:metabolism; D009875:Operator Regions, Genetic / Q000235:genetics; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D007477:Ions; D046911:Macromolecular Substances; D009698:Nucleoproteins; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D007501:Iron