Quorum sensing in
Escherichia coli
,
Salmonella typhimurium
, and
Vibrio harveyi
: A new family of genes responsible for autoinducer production
Journal Articles
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
In bacteria, the regulation of gene expression in response to
changes in cell density is called quorum sensing. Quorum-sensing
bacteria produce, release, and respond to hormone-like molecules
(autoinducers) that accumulate in the external environment as the cell
population grows. In the marine bacterium
Vibrio harveyi
two parallel quorum-sensing systems exist, and each is composed of a
sensor–autoinducer pair.
V. harveyi
reporter strains
capable of detecting only autoinducer 1 (AI-1) or autoinducer 2 (AI-2)
have been constructed and used to show that many species of bacteria,
including
Escherichia coli
MG1655,
E.
coli
O157:H7,
Salmonella typhimurium
14028, and
S. typhimurium
LT2 produce autoinducers similar or
identical to the
V. harveyi
system 2 autoinducer AI-2.
However, the domesticated laboratory strain
E. coli
DH5α does not produce this signal molecule. Here we report the
identification and analysis of the gene responsible for AI-2 production
in
V. harveyi
,
S. typhimurium
, and
E. coli
. The genes, which we have named
luxS
V.h.
,
luxS
S.t.
, and
luxS
E.c.
respectively, are highly homologous
to one another but not to any other identified gene.
E.
coli
DH5α can be complemented to AI-2 production by the
introduction of the
luxS
gene from
V.
harveyi
or
E. coli
O157:H7. Analysis of the
E. coli
DH5α
luxS
E.c.
gene
shows that it contains a frameshift mutation resulting in premature
truncation of the LuxS
E.c.
protein. Our
results indicate that the
luxS
genes define a new family
of autoinducer-production genes.
