MRNA context dependent regulation of cytotoxic necrotizing factor 1 translation by GidA, a tRNA modification enzyme in Escherichia coli

Research output: Contribution to journalArticlepeer-review

Abstract

Cytotoxic necrotizing factor 1 (CNF1), the paradigm of Rho GTPase activating bacterial toxins has been shown to promote E. coli invasion of human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier, but its synthesis and secretion is unclear. In this study, we performed mini Tn5 mutagenesis screen to identify genetic requirements for CNF1 production and secretion. Transposon mutagenesis screen of meningitis-causing E. coli K1 strain RS218 revealed that CNF1 production was markedly decreased in a transposon mutant (NBC-28G9) where transposon insertion occurred in the 5' end of gidA gene. In contrast, total deletion of gidA gene has less drastic effect on the production of CNF1. The N-terminus truncated GidA exhibited dominant negative effect on the production of CNF1. The inhibition of CNF1 production by N-terminus truncated GidA was shown to occur at the translational level. This was supported by our demonstrations that cnf1 mRNA transcription levels did not differ between strains RS218 and NBC-28G9; and the production of recombinant CNF1 under the control of artificial promoter was also repressed by truncated GidA. Progressive deletion of DNA regions in cnf1 gene identified two putative regions that were responsible for translational inhibition mediated by truncated GidA.

Original languageEnglish (US)
Pages (from-to)116-122
Number of pages7
JournalGene
Volume491
Issue number2
DOIs
StatePublished - Jan 10 2012

Keywords

  • CNF1
  • E. coli
  • Gene expression
  • GidA
  • MRNA

ASJC Scopus subject areas

  • Genetics

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