Expression of the O antigen gene cluster is regulated by RfaH through the JUMPstart sequence

FEMS Microbiol Lett. 1998 Aug 1;165(1):201-6. doi: 10.1111/j.1574-6968.1998.tb13147.x.


O antigen genes are clustered, with a JUMPstart sequence located upstream. JUMPstart is a 39-bp sequence, present upstream of many polysaccharide gene clusters and also upstream of haemolysin and F factor gene clusters. RfaH is known to regulate the expression of E. coli group II capsule, haemolysin, F factor and the outer core of lipopolysaccharide all of which have the JUMPstart sequence, and has been shown to function as a transcriptional antiterminator in some cases. Using lacZ fusions to genes in the O antigen gene cluster of Salmonella enterica serovar Typhimurium, we found that RfaH also regulates the expression of O antigen. We showed that RfaH enhances expression of the 18-kb O antigen gene cluster, with promoter-distal genes affected more dramatically. We also showed that the JUMPstart sequence was required for RfaH function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Bacterial / genetics*
  • Bacterial Proteins / genetics*
  • Cloning, Molecular
  • Escherichia coli / genetics
  • Escherichia coli / immunology
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial / genetics*
  • Genes, Regulator / genetics*
  • Mutagenesis, Insertional
  • O Antigens*
  • Peptide Elongation Factors / genetics*
  • Salmonella enterica / genetics
  • Salmonella enterica / immunology
  • Trans-Activators / genetics*


  • Antigens, Bacterial
  • Bacterial Proteins
  • Escherichia coli Proteins
  • O Antigens
  • Peptide Elongation Factors
  • RfaH protein, E coli
  • Trans-Activators