Disease relevance of fimA

• The on-and-off expression (phase variation) of type 1 fimbriae, encoded by fimA, in Escherichia coli is controlled by the inversion of a promoter-containing 314-base-pair DNA element [1].
• From a cosmid clone, a 5.3-kilobase (kb) HindIII fragment of Salmonella enteritidis DNA containing the fimA gene was subcloned into bacteriophage T7 promoter vectors in both orientations [2].
• Our inability to obtain simple pilA- mutants strongly suggests that pilA is an essential gene in the gonococcus [3].
• We have previously reported the identification of two genes, pilA and pilB, which act in trans to regulate pilus expression in Neisseria gonorrhoeae [4].
• The polar pili of Pseudomonas aeruginosa are composed of subunits encoded by the pilA gene [5].

High impact information on fimA

• The pilA and pilB genes are in opposite orientation relative to each other, and the 5' ends of the two genes overlap [3].
• DNA sequence analysis shows that the pilA and pilB loci encode proteins of 38.6 kd (with a putative DNA binding domain) and 57.9 kd respectively [3].
• A pilA clone activates the pilin promoter in Escherichia coli, and a pilA-/pilA+ heterodiploid gonococcus exhibits a P- phenotype [3].
• We have identified two closely linked genes, pilA and pilB, which act in trans on the pilin promoter. pilA-pilB map downstream of expression loci pilE1 and opaE1 in the gonococcal chromosome [3].
• The pilA gene of Neisseria gonorrhoeae encodes the response regulator of a two-component regulatory system that controls pilin gene expression [6].

Biological context of fimA

• A model is presented to account for the effects of lost topoisomerase function on fimA gene expression [7].
• Southern hybridization and polymerase chain reaction analyses of the fimA promoter region in broth-grown 149 cells indicated that the invertible element was present in orientations corresponding to both Pil+ and Pil- phenotypes [8].
• Molecular phylogenetic analyses of the fimA and fimI genes yield an estimate of phylogeny that is in satisfactory congruence with housekeeping and other virulence genes examined in this species [9].
• The nucleotide sequence was determined of a region of 1450 base pairs encompassing the fimA gene for the subunit of type 1 fimbriae of Escherichia coli as well as flanking regions containing potential regulator sequences [10].
• No correlation was found between the fimH and fimA sequences and the following parameters: avian species, organ of isolation, serotype, presence of aerobactin receptor and virulence for chickens [11].

Associations of fimA with chemical compounds

• Transcription from the fimA promoter was unaffected by changes in DNA supercoiling whether caused by the introduction of a topA::Tn10 mutation or by inhibition of DNA gyrase with the antibiotic novobiocin [7].

Other interactions of fimA

• This effect was more pronounced in high-osmolarity acidic media; fimB and fimA expression decreased fivefold in growth media containing 800 mM NaCl compared to expression in growth media without added NaCl [12].
• Studies using the fimY-lacZ construct reveal that expression of this gene varies with environmental conditions in a manner similar to fimA expression [13].
• The fourth complementation group was composed of a large number of mutants defective in both pilA and pilB functions [14].
• The pattern of complementation defined three cistrons involved in pilus formation, pilA, pilB, and pilC [14].
• Sequence analysis demonstrates the conservation of fimH and variability of fimA throughout avian pathogenic Escherichia coli (APEC) [11].

References