Biomaterial Database

Positive autoregulation of the flhDC operon in Proteus mirabilis. 2018

Kristen E Howery, and Emrah Şimşek, and Minsu Kim, and Philip N Rather

Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA.

Using a variety of techniques, we demonstrate the Class I regulator of the flagellar cascade, FlhD4C2, can activate its own expression in Proteus mirabilis. This activation was direct, as the FlhD4C2 protein specifically bound to its promoter region. The expression of bacterial genes under a positive feedback control can exhibit varying levels between cells due to stochastic fluctuations that activate the feedback loop and result in some cells in an "ON" state. Cells containing a chromosomal flhDC::gfp transcriptional fusion exhibited a heterogeneous pattern of expression within the population during growth on agar surfaces and the percentage of cells expressing GFP increased as cells approached swarmer cell differentiation. Disrupting the FlhD4C2 -mediated positive feedback loop significantly reduced the frequency of cells exhibiting GFP expression.

UI	MeSH Term	Description	Entries
D009068	Movement	The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.	Movements
D011401	Promoter Regions, Genetic	DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.	rRNA Promoter,Early Promoters, Genetic,Late Promoters, Genetic,Middle Promoters, Genetic,Promoter Regions,Promoter, Genetic,Promotor Regions,Promotor, Genetic,Pseudopromoter, Genetic,Early Promoter, Genetic,Genetic Late Promoter,Genetic Middle Promoters,Genetic Promoter,Genetic Promoter Region,Genetic Promoter Regions,Genetic Promoters,Genetic Promotor,Genetic Promotors,Genetic Pseudopromoter,Genetic Pseudopromoters,Late Promoter, Genetic,Middle Promoter, Genetic,Promoter Region,Promoter Region, Genetic,Promoter, Genetic Early,Promoter, rRNA,Promoters, Genetic,Promoters, Genetic Middle,Promoters, rRNA,Promotor Region,Promotors, Genetic,Pseudopromoters, Genetic,Region, Genetic Promoter,Region, Promoter,Region, Promotor,Regions, Genetic Promoter,Regions, Promoter,Regions, Promotor,rRNA Promoters
D011513	Proteus mirabilis	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is frequently isolated from clinical specimens. Its most common site of infection is the urinary tract.
D005407	Flagella	A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Flagellum
D005408	Flagellin	A protein with a molecular weight of 40,000 isolated from bacterial flagella. At appropriate pH and salt concentration, three flagellin monomers can spontaneously reaggregate to form structures which appear identical to intact flagella.
D015534	Trans-Activators	Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.	Nuclear Trans-Acting Factor,Trans-Acting Factors,Trans-Acting Factor,Trans-Activator,Transactivator,Transactivators,Factor, Nuclear Trans-Acting,Factor, Trans-Acting,Factors, Trans-Acting,Nuclear Trans Acting Factor,Trans Acting Factor,Trans Acting Factors,Trans Activator,Trans Activators,Trans-Acting Factor, Nuclear
D015964	Gene Expression Regulation, Bacterial	Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.	Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial
D049452	Green Fluorescent Proteins	Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.	Green Fluorescent Protein,Green-Fluorescent Protein,Green-Fluorescent Proteins,Fluorescent Protein, Green,Fluorescent Proteins, Green,Protein, Green Fluorescent,Protein, Green-Fluorescent,Proteins, Green Fluorescent,Proteins, Green-Fluorescent
D025461	Feedback, Physiological	A mechanism of communication with a physiological system for homeostasis, adaptation, etc. Physiological feedback is mediated through extensive feedback mechanisms that use physiological cues as feedback loop signals to control other systems.	Feedback, Biochemical,Feedback Inhibition, Biochemical,Feedback Regulation, Biochemical,Feedback Stimulation, Biochemical,Negative Feedback, Biochemical,Positive Feedback, Biochemical,Biochemical Feedback,Biochemical Feedback Inhibition,Biochemical Feedback Inhibitions,Biochemical Feedback Regulation,Biochemical Feedback Regulations,Biochemical Feedback Stimulation,Biochemical Feedback Stimulations,Biochemical Feedbacks,Biochemical Negative Feedback,Biochemical Negative Feedbacks,Biochemical Positive Feedback,Biochemical Positive Feedbacks,Feedback Inhibitions, Biochemical,Feedback Regulations, Biochemical,Feedback Stimulations, Biochemical,Feedback, Biochemical Negative,Feedback, Biochemical Positive,Feedbacks, Biochemical,Feedbacks, Biochemical Negative,Feedbacks, Biochemical Positive,Feedbacks, Physiological,Inhibition, Biochemical Feedback,Inhibitions, Biochemical Feedback,Negative Feedbacks, Biochemical,Physiological Feedback,Physiological Feedbacks,Positive Feedbacks, Biochemical,Regulation, Biochemical Feedback,Regulations, Biochemical Feedback,Stimulation, Biochemical Feedback,Stimulations, Biochemical Feedback