Disease relevance of fleQ

• The alternative sigma factor AlgT represses Pseudomonas aeruginosa flagellum biosynthesis by inhibiting expression of fleQ [1].
• Thus, our data show that AlgT inhibits flagellum biosynthesis in mucoid, nonmotile P. aeruginosa cystic fibrosis isolates by promoting expression of AmrZ, which subsequently represses fleQ [2].

High impact information on fleQ

• A polymorphic locus flanked by flgJ and fleQ in Region I contains a glycosylation island in PAK [3].
• Class I genes are constitutively expressed and include the transcriptional regulator fleQ and the alternative sigma factor fliA (sigma28) [3].
• The results of the beta-galactosidase assays suggest that the fliD gene in P. aeruginosa is regulated by the newly described transcriptional regulator FleQ and the alternate sigma factor sigma54 (RpoN) [4].
• Previous work has shown that repression of fleQ by AlgT accounts for the loss of flagellum biosynthesis in these strains [2].
• Vfr probably represses fleQ transcription by binding to the Vfr binding site in the fleQ promoter and preventing the sigma factor from binding to the -10 region to initiate transcription [5].

Biological context of fleQ

• We therefore examined the regulation of the fleSR operon by fleQ and vice versa [6].
• Primer extension analysis of the fleQ transcript revealed two transcriptional start sites, t1 and t2, that map within the Vfr binding site [5].
• Both of these functions were regained by providing the complete fleQ gene on a multicopy plasmid [6].
• Except for the posttranslational downregulation of FleQ activity by FleN, an antiactivator, not much is known about the regulation of the fleQ gene or its gene product [5].
• The complete nucleotide sequence of the fleQ gene was determined on both DNA strands, and an open reading frame (ORF) consisting of 1,493 nucleotides was identified [6].

Other interactions of fleQ

• The fleQ gene is flanked by a flagellar operon, fliDSorf126, at the 5' end and the fleSR operon on the 3' end [6].

Analytical, diagnostic and therapeutic context of fleQ

• Electrophoretic mobility shift assays using purified AlgT and extracts derived from isogenic AlgT(+) and AlgT(-) strains revealed that AlgT inhibits fleQ indirectly [2].

References