This family includes bacterial transcriptional regulators that are thought to act through an interaction with the conserved region 4 of the sigma(70) subunit of RNA polymerase. The Pseudomonas aeruginosa homologue, AlgQ, positively regulates virulence gene expression and is associated with the mucoid phenotype observed in Pseudomonas aeruginosa isolates from cystic fibrosis patients.

1: Bacterial two-hybrid analysis of interactions between region 4 of the sigma(70) subunit of RNA polymerase and the transcriptional regulators Rsd from Escherichia coli and AlgQ from Pseudomonas aeruginosa. Dove SL, Hochschild A; J Bacteriol 2001;183:6413-6421. PMID:11591686