The rfaH gene, which affects lipopolysaccharide synthesis in Salmonella enterica serovar Typhi, is differentially expressed during the bacterial growth phase

Gonzalo Rojas, Soledad Saldías, Mauricio Bittner, Mercedes Zaldívar, Inés Contreras

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

We have cloned and sequenced the rfaH gene from Salmonella enterica serovar Typhi strain Ty2. The gene showed a high degree of similarity to the rfaH genes from Escherichia coli K-12 and S. enterica serovar Typhimurium. A rfaH mutant was constructed by site-directed mutagenesis. This mutant produced a rough lipopolysaccharide (LPS), with an incomplete core region. The defect in LPS expression that results from the rfaH mutation was corrected by a plasmid carrying the intact gene. The plasmid-borne rfaH gene also restored normal LPS synthesis in a rfaH mutant of E. coli. Reverse transcription-polymerase chain reaction analyses were performed to determine the effects of various environmental conditions on the expression of rfaH. The transcription of rfaH showed a growth-phase-dependent regulation, with maximal expression at the late exponential phase. Other environmental conditions, such as temperature or medium osmolarity, did not affect transcription of rfaH.

Original languageEnglish
Pages (from-to)123-128
Number of pages6
JournalFEMS Microbiology Letters
Volume204
Issue number1
DOIs
Publication statusPublished - 16 Oct 2001

Keywords

  • Lipopolysaccharide
  • RfaH
  • Salmonella typhi

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics

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