Disease relevance of rfaH

• We confirmed that deletion of rfaH leads to increased levels of flu and flu-like transcripts in E. coli K-12 and UPEC [1].
• Mutations in rfaH and galU strongly reduced alpha-haemolysin secretion as well as the secretion of Erwinia chrysanthemi proteases in E. coli without affecting their synthesis [2].
• We cloned the rfaH genes from Vibrio cholerae, Yersinia enterocolitica, S. enterica serovar Typhimurium, and Klebsiella pneumoniae into E. coli expression vectors [3].

High impact information on rfaH

• However additional mutations mapped in genes rfaH and galU which are required for lipopolysaccharide (LPS) biosynthesis [2].
• We have identified, by transposon mutagenesis, an E. coli cellular locus, hlyT, required for the synthesis and secretion of haemolysin encoded in trans by intact hly operons carrying the hly upstream regulatory region [4].
• Only inactivation of rfaH, which encodes a transcriptional antiterminator, resulted in increased initial adhesion and biofilm formation by E. coli 536. rfaH inactivation in nonpathogenic E. coli K-12 isolate MG1655 resulted in the same phenotype [1].
• An rfaH mutation abolished K10 capsule production, suggesting that expression of the K10 capsule was regulated by RfaH in a manner analogous to group II capsule gene clusters [5].
• Extraintestinal pathogenic (ExPEC) as well as non-pathogenic probiotic E. coli strains rapidly outcompeted their isogenic rfaH mutants following oral mixed infections [6].

Chemical compound and disease context of rfaH

• Escherichia coli HlyT protein, a transcriptional activator of haemolysin synthesis and secretion, is encoded by the rfaH (sfrB) locus required for expression of sex factor and lipopolysaccharide genes [4].

Associations of rfaH with chemical compounds

• Our results demonstrate that the strong initial adhesion and biofilm formation capacities of strain MG1655rfaH are mediated by both increased steady-state production of Ag43 and likely increased Ag43 presentation due to null rfaH-dependent lipopolysaccharide depletion [1].

References