Biomaterial Database

Intergenic suppression between the flagellar MS ring protein FliF of Salmonella and FlhA, a membrane component of its export apparatus. 2001

M Kihara, and T Minamino, and S Yamaguchi, and R M Macnab

Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA.

The MS ring of the flagellar basal body of Salmonella is an integral membrane structure consisting of about 26 subunits of a 61-kDa protein, FliF. Out of many nonflagellate fliF mutants tested, three gave rise to intergenic suppressors in flagellar region II. The pseudorevertants swarmed, though poorly; this partial recovery of motile function was shown to be due to partial recovery of export function and flagellar assembly. The three parental mutants were all found to carry the same mutation, a six-base deletion corresponding to loss of Ala-174 and Ser-175 in the predicted periplasmic domain of the FliF protein. The 19 intergenic suppressors identified all lay in flhA, and they consisted of 10 independent examples at the nucleotide level or 9 at the amino acid level. Since two of the nine corresponded to different substitutions at the same amino acid position, only eight positions in the FlhA protein have given rise to suppressors. Thus, FliF-FlhA intergenic suppression is a fairly rare event. FlhA is a component of the flagellar protein export apparatus, with an integral membrane domain encompassing the N-terminal half of the sequence and a cytoplasmic C-terminal domain. All of the suppressing mutations lay within the integral membrane domain. These mutations, when placed in a wild-type fliF background, had no mutant phenotype. In the fliF mutant background, mutant FlhA was dominant, yielding a pseudorevertant phenotype. Wild-type FlhA did not exert significant negative dominance in the pseudorevertant background, indicating that it does not compete effectively with mutant FlhA for interaction with mutant FliF. Mutant FliF was partially dominant over wild-type FliF in both the wild-type and second-site FlhA backgrounds. Membrane fractionation experiments indicated that the fliF mutation, though preventing export, was mild enough to permit assembly of the MS ring itself, and also assembly of the cytoplasmic C ring onto the MS ring. The data from this study provide genetic support for a model in which at least the FlhA component of the export apparatus physically interacts with the MS ring within which it is housed.

UI	MeSH Term	Description	Entries
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
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
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
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
D005799	Genes, Dominant	Genes that influence the PHENOTYPE both in the homozygous and the heterozygous state.	Conditions, Dominant Genetic,Dominant Genetic Conditions,Genetic Conditions, Dominant,Condition, Dominant Genetic,Dominant Gene,Dominant Genes,Dominant Genetic Condition,Gene, Dominant,Genetic Condition, Dominant
D005816	Genetic Complementation Test	A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.	Allelism Test,Cis Test,Cis-Trans Test,Complementation Test,Trans Test,Allelism Tests,Cis Tests,Cis Trans Test,Cis-Trans Tests,Complementation Test, Genetic,Complementation Tests,Complementation Tests, Genetic,Genetic Complementation Tests,Trans Tests
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D012475	Salmonella	A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that utilizes citrate as a sole carbon source. It is pathogenic for humans, causing enteric fevers, gastroenteritis, and bacteremia. Food poisoning is the most common clinical manifestation. Organisms within this genus are separated on the basis of antigenic characteristics, sugar fermentation patterns, and bacteriophage susceptibility.
D013489	Suppression, Genetic	Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).	Suppressor Mutation,Genetic Suppression,Genetic Suppressions,Mutation, Suppressor,Mutations, Suppressor,Suppressions, Genetic,Suppressor Mutations