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Examination of regulatory cross-talk between the decay accelerating factor-binding fimbrial/afimbrial adhesins and

N Holden1, C Cotterill, D Gally

  • 1Department of Veterinary Pathology, Royal (Dick) School of Veterinary Studies, University of Edinburgh.

Advances in Experimental Medicine and Biology
|December 8, 2000
PubMed

Insights

The protein DaaA, similar to regulator AFAA-III, does not repress type 1 fimbriae switching like PapB. PapB, not DaaA, reduced type 1 fimbriae expression, suggesting PapB

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacteriology

Background:

  • Type 1 fimbriae are crucial virulence factors in uropathogenic Escherichia coli (UPEC).
  • Regulation of type 1 fimbriae expression involves complex genetic pathways, including the FimB/FimE switch.
  • PapB is a known regulator involved in the expression of P-fimbriae, but its interaction with type 1 fimbriae is less understood.

Purpose of the Study:

  • To investigate the regulatory role of DaaA protein in type 1 fimbriae expression.
  • To compare the regulatory function of DaaA with PapB concerning type 1 fimbriae switching.
  • To identify potential cross-talk mechanisms between P-fimbriae and type 1 fimbriae regulatory systems.

Main Methods:

  • Comparative sequence analysis of DaaA and afimbrial adhesin regulator AFAA-III.
  • Assessment of FimB OFF to ON switching in bacterial strains expressing DaaA and PapB.
  • Quantification of type 1 fimbriae expression levels in static Luria-Bertani (LB) media.

Main Results:

  • DaaA exhibits 98% sequence identity to afimbrial adhesin regulator AFAA-III.
  • Unlike PapB, DaaA did not repress the FimB OFF to ON switching in strain AAEC370A.
  • PapB, but not DaaA, significantly reduced type 1 fimbriae expression in static LB media.

Conclusions:

  • DaaA does not appear to directly repress type 1 fimbriae switching.
  • PapB plays a role in downregulating type 1 fimbriae expression, suggesting regulatory cross-talk.
  • The amino terminus of PapB is a potential domain involved in the observed cross-talk with type 1 fimbriae regulation.

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