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Infection and Immunity, October 1999, p. 5455-5462, Vol. 67, No. 10
Institute of Medical Science,
Received 30 April 1999/Returned for modification 18 June
1999/Accepted 9 July 1999
The complete nucleotide sequence and organization of the
enteropathogenic Escherichia coli (EPEC) adherence factor
(EAF) plasmid of EPEC strain B171 (O111:NM) were determined. The EAF
plasmid encodes two known virulence-related operons, the
bfp operon, which is composed of genes necessary for
biosynthesis of bundle-forming pili, and the bfpTVW
(perABC) operon, composed of regulatory genes required for
bfp transcription and also for transcriptional activation of the eae gene in the LEE pathogenicity island on the EPEC
chromosome. The 69-kb EAF plasmid, henceforth designated pB171,
contains, besides the bfp and bfpTVW
(perABC) operons, potential virulence-associated genes,
plasmid replication and maintenance genes, and many insertion sequence
elements. Of the newly identified open reading frames (ORFs), two which
comprise a single operon had the potential to encode proteins with high
similarity to a C-terminal region of ToxB whose coding sequence is
located on pO157, a large plasmid harbored by enterohemorrhagic
E. coli. Another ORF, located between the bfp
and bfpTVW operons, showed high similarity with
trcA, a bfpT-regulated chaperone-like protein
gene of EPEC. Two sites were found to be putative replication regions:
one similar to RepFIIA of p307 or F, and the other similar to RepFIB of
R100 (NR1). In addition, we identified a third region that contains plasmid maintenance genes. Insertion elements were scattered throughout the plasmid, indicating the mosaic nature of the EAF plasmid and suggesting evolutionary events by which virulence genes may have been obtained.
0019-9567/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Complete DNA Sequence and Structural Analysis of
the Enteropathogenic Escherichia coli Adherence Factor
Plasmid
*
Corresponding author. Mailing address: Department of
Bacteriology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan. Phone: 81-3-5449-5537. Fax: 81-3-5449-5405. E-mail:
torutobe{at}ims.u-tokyo.ac.jp.
Infection and Immunity, October 1999, p. 5455-5462, Vol. 67, No. 10
0019-9567/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
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