Role of the htrA Gene in Klebsiella pneumoniae Virulence
AUTOR(ES)
Cortés, Guadalupe
FONTE
American Society for Microbiology
RESUMO
We recently described the use of mini-Tn5 to generate complement-sensitive mutants derived from a complement-resistant Klebsiella pneumoniae clinical isolate deficient in the lipopolysaccharide O side chain. One mutant with a reduced capacity to survive in nonimmune human sera carried the transposon inserted in the htrA gene. We cloned and sequenced the gene and predicted from the deduced amino acid sequence that the putative HtrA homolog contains structural features similar to those of previously described HtrA proteins. To investigate the biological functions and the role of the htrA gene in the virulence of K. pneumoniae, we constructed an isogenic mutant by insertion-duplication mutagenesis. Characterization of the mutant showed that it had greater sensitivity to temperature (50°C) and oxidative stress (H2O2) than the parent strain. Furthermore, the htrA mutant produced less capsule, bound more molecules of complement component C3, and was more sensitive to complement and whole-blood killing than was the parent strain. Finally, disruption of the htrA gene in a virulent K. pneumoniae strain caused a reduction of its virulence in a mice model. Our results indicate that the htrA gene plays an important role in the virulence of K. pneumoniae.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=128236Documentos Relacionados
- Role of HtrA in the Virulence and Competence of Streptococcus pneumoniae
- Role for Serine Protease HtrA (DegP) of Streptococcus pyogenes in the Biogenesis of Virulence Factors SpeB and the Hemolysin Streptolysin S
- Control of Virulence by the Two-Component System CiaR/H Is Mediated via HtrA, a Major Virulence Factor of Streptococcus pneumoniae
- Transcriptional Activation of the htrA (High-Temperature Requirement A) Gene from Bartonella henselae
- The Klebsiella pneumoniae wabG Gene: Role in Biosynthesis of the Core Lipopolysaccharide and Virulence