PilR, a transcriptional regulator of piliation in Pseudomonas aeruginosa, binds to a cis-acting sequence upstream of the pilin gene promoter

Mol Microbiol. 1994 Dec;14(5):1049-57. doi: 10.1111/j.1365-2958.1994.tb01338.x.


The PilR protein of Pseudomonas aeruginosa is a transcriptional activator of the pilin gene and belongs to a two-component sensor-regulator family. PilR was overproduced by fusing pilR to the gene for the maltose-binding protein (malE), yielding a MalE-PilR hybrid protein. The plasmid with the malE-pilR fusion, when introduced into a non-piliated pilR mutant strain of P. aeruginosa, restored piliation, indicating that the hybrid protein retains PilR function in vivo. The MalE-PilR protein was purified from Escherichia coli and used in a series of DNA-binding studies. A specific pilin promoter-binding activity of MalE-PilR was observed in a gel retardation assay. Subsequent DNase I footprinting analysis revealed a 40 bp PilR-binding site located at the -120 to -80 region, relative to the transcriptional start site of the pilin gene. This PilR-binding region consists of a nine-base sequence and three consensus sequences of 5'-(N)4-6C/GTGTC-3', in a tandem array in which the first 7-9 bp are bound by the PilR on the non-coding strand, leaving the last two nucleotides (TC) unbound. On the coding strand, PilR binds to sequences complementary to the two middle consensus sequences of the non-coding strand. A sequence similar to the NifA recognition site (5'-TGT-(N)11-ACA-3') is also found within the PilR-binding region. Deletion analysis and disruption of the individual consensus PilR-binding sequences by site-directed mutagenesis revealed that all four PilR-binding sites are absolutely required for the PilS/PilR-mediated pilin gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites / genetics
  • DNA, Bacterial / genetics
  • Escherichia coli / genetics
  • Fimbriae Proteins
  • Fimbriae, Bacterial / metabolism
  • Gene Expression
  • Genes, Bacterial
  • Molecular Sequence Data
  • Plasmids / genetics
  • Promoter Regions, Genetic
  • Pseudomonas aeruginosa / genetics*
  • Pseudomonas aeruginosa / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DNA, Bacterial
  • Transcription Factors
  • pilR protein, Pseudomonas aeruginosa
  • Fimbriae Proteins