Table 1.

Genes and cellular activities regulated by PhoP-PhoQ inSalmonella

GeneFunction and /or properties of gene productPresent inE. coli K-12?
hilA Transcriptional regulator of invasion genesNo
mgtA P-type ATPase Mg2+transporterYes
mgtB P-type ATPase Mg2+ transporterNo
mgtC Mg2+ acquisition; intramacrophage survivalNo
pagC Outer membrane protein with sequence similarity to EnterobacterOmpX, Yersinia Ail, and phage lambda LomNo
pagP Outer membrane enzyme mediating transfer of palmitate to lipid A; resistance to peptide C18GYes
pbgPEoperonSynthesis and/or incorporation of 4-aminoarabinose into lipid A; resistance to polymyxinYes
pcgL Periplasmic d-Ala-d-Ala dipeptidaseNoa
pgtE Outer membrane protease; resistance to peptide C18GNoa
phoN Periplasmic nonspecific acid phosphataseNo
phoPQ Mg2+ -responding two-component systemYes
pmrAB Fe3+ -responding two-component systemYes
pmrD Mediator of transcriptional activation of pmrA-regulated genes during growth in low Mg2+ Yes
prgHIJK Components of Inv-Spa type III secretion systemNo
spvB Mono(ADP-ribosyl)transferase encoded in Salmonella virulence plasmidNo
ugd UDP-d-glucose dehydrogenaseYes
ugtL Putative membrane proteinNo
  • a E. coli K-12 harbors two genes,ecovanX and ompT, encoding products that are only 40 and 46% identical to the Salmonella pcgL andpgtE gene products, respectively. However, these genes are not true homologs and, like Salmonella pcgL andpgtE, the E. coli genes appear to have been acquired horizontally.