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DNA microarray analysis of fim mutations in Escherichia coli
M A Schembri1, D W Ussery, C Workman
1Microbial Adhesion Group, Section of Molecular Microbiology, Bldg. 301, BioCentrum-DTU, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Molecular Genetics and Genomics : MGG
|September 11, 2002
Summary
Escherichia coli type 1 fimbriae are complex protein structures crucial for bacterial adhesion and virulence. DNA microarray analysis revealed insights into the regulation of fimbrial gene expression and its impact on cell surface characteristics.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Bacterial adhesion is mediated by surface structures like fimbriae.
- Type 1 fimbriae in Escherichia coli are well-characterized adhesive organelles involved in D-mannose binding and urinary tract virulence.
- Fimbrial production represents a significant cellular resource investment.
Purpose of the Study:
- To investigate the molecular events underlying fimbrial gene expression in E. coli K-12 using DNA microarray analysis.
- To correlate changes in fimbrial gene expression with cellular phenotypes.
- To explore the regulatory network involving fimbrial genes and other surface proteins.
Main Methods:
- DNA microarray analysis of E. coli K-12 to examine fim gene expression.
- Construction of gene deletion mutants (entire fim cluster, fimH gene).
- Assessment of colony morphology and surface protein expression (Antigen 43).
Main Results:
- Differential expression levels of fim genes aligned with known fimbrial stoichiometry.
- Changes in fim gene expression correlated with altered colony morphology.
- Deletion of the fim gene cluster led to converse expression of Antigen 43; fimH deletion reduced fimbriae number without affecting other fim genes or Ag43.
Conclusions:
- DNA microarray analysis provides a comprehensive view of fimbrial gene expression regulation in E. coli.
- Fimbrial gene expression is intricately linked to cellular resource allocation and surface protein regulation.
- The fimH gene is critical for fimbrial assembly but not for the regulation of other fim genes or Antigen 43 expression.