Identification and sequencing of the groE operon and flanking genes of Lawsonia intracellularis: Use in phylogeny

C. Jane H. Dale, Eric K. Moses, Chin Chui Ong, Chris J. Morrow, Michael B. Reed, Dete Hasse, Richard A. Strugnell

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Proliferative enteropathy (PE) is a complex of diseases of commercial importance to the pig industry. The obligate intracellular bacterium Lawsonia infracellularis is consistently associated with PE and pure cultures of this bacterium have been used to reproduce PE in pigs. In this study L. intracellularis bacteria were purified directly from PE-affected tissue. DNA extracted from purified bacteria was used to construct a partial genomic library which was screened using sera from L. intracellularis-immunized rabbits. Two seroreactive recombinant clones were identified, one of which expressed proteins of 10 and 60 kDa. The sequence of the insert from this clone, pISI-2, revealed ORFs with sequence similarity to the groES/EL operon of Escherichia coli, the 50S ribosomal proteins L21 and L27 of E. coli, a GTP-binding protein of Bacillus subtilis and a possible protoporphyrinogen oxidase, HemK, of E. coli. Primers designed from unique sequences from the pISI-2 insert amplified DNA from infected, but not non-infected, porcine ilea; the amplicon sequence obtained from tissue-cultured L. intracellularis was identical to the corresponding sequence in pISI-2, confirming the origin of the clone. The sequence of L. intracellularis GroEL and other GroEL sequences in the databases were used to construct a partial phylogenetic tree. Analysis of the GroEL sequence relationship suggested that L. intracellularis is not significantly related to other organisms whose GroEL sequences are held in the databases and supports previous data from 16S sequence analyses suggesting that L. intracellularis is a member of a novel group of enteric pathogens.

Original languageEnglish (US)
Pages (from-to)2073-2084
Number of pages12
Issue number8
StatePublished - Aug 1998
Externally publishedYes


  • Heat-shock protein
  • Lawsonia intracellularis
  • Proliferative enteropathy
  • groE operon

ASJC Scopus subject areas

  • Microbiology


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