In:
Journal of Bacteriology, American Society for Microbiology, Vol. 187, No. 9 ( 2005-05), p. 2927-2938
Kurzfassung:
Legionella
pneumophila is able to survive inside phagocytic cells by an
internalization route that bypasses fusion of the nascent phagosome with the endocytic pathway to allow formation of a replicative
phagosome. The dot/icm genes, a major virulence system of L. pneumophila , encode a type IVB secretion system that is
required for intracellular growth. One Dot protein, DotL, has sequence similarity to type IV secretion system coupling proteins (T4CPs). In
other systems, coupling proteins are not required for viability of the organism. Here we report the first example of a strain, L.
pneumophila Lp02, in which a putative T4CP is essential for
viability of the organism on bacteriological media. This result is particularly surprising since the majority of the dot/icm genes in Lp02 are dispensable for growth outside of a host cell, a
condition that does not require a functional Dot/Icm secretion complex. We were able to isolate suppressors of the ΔdotL lethality and found that many contained mutations in other components
of the Dot/Icm secretion system. A systematic analysis of dot/icm deletion mutants revealed that the majority of them
(20 of 26) suppressed the lethality phenotype, indicating a partially assembled secretion system may be the source of ΔdotL toxicity in the wild-type strain. These results are consistent with a
model in which the DotL protein plays a role in regulating the activity of the L. pneumophila type IV secretion
apparatus.
Materialart:
Online-Ressource
ISSN:
0021-9193
,
1098-5530
DOI:
10.1128/JB.187.9.2927-2938.2005
Sprache:
Englisch
Verlag:
American Society for Microbiology
Publikationsdatum:
2005
ZDB Id:
1481988-0
SSG:
12
