Previous Article | Next Article 
Infection and Immunity, July 2000, p. 3971-3982, Vol. 68, No. 7
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Identification and Subcellular Localization of the
Legionella pneumophila IcmX Protein: a Factor Essential
for Establishment of a Replicative Organelle in Eukaryotic
Host Cells
Miguelina
Matthews and
Craig R.
Roy*
Section of Microbial Pathogenesis, Yale
University School of Medicine, Boyer Center for Molecular Medicine,
New Haven, Connecticut 06536-0812
Received 14 February 2000/Returned for modification 30 March
2000/Accepted 24 April 2000
The gram-negative respiratory pathogen Legionella
pneumophila infects and grows within mammalian macrophages and
protozoan host cells. Upon uptake into macrophages, L. pneumophila establishes a replicative organelle that avoids
fusion with endocytic vesicles. There are 24 dot/icm genes
on the L. pneumophila chromosome required for biogenesis of
this vacuole. Many of the Dot/Icm proteins are predicted to be
components of a membrane-bound secretion apparatus similar to type IV
conjugal transfer systems. We have been investigating the function of
L. pneumophila dot/icm gene products that do not have
obvious orthologs in other type IV transfer systems, since these
determinants could govern processes unique to phagosome biogenesis. The
icmX gene product falls into this category. To understand
the role of the IcmX protein in pathogenesis, we have detailed
interactions between an L. pneumophila icmX deletion mutant
and murine bone marrow-derived macrophages. These data demonstrate that
icmX is required for biogenesis of the L. pneumophila replicative organelle. Immunoblot analysis indicates
that the icmX gene product is a polypeptide with an
estimated molecular mass of 50 kDa. The IcmX protein was localized to
the bacterial periplasm, and periplasmic translocation was mediated by
an N-terminal sec-dependent leader peptide. A truncated
IcmX product was secreted into culture supernatants by wild-type
L. pneumophila growing extracellularly in liquid media;
however, transport of the IcmX protein into eukaryotic host cells was
not detected. Proteins similar in molecular weight to IcmX were
identified in other Legionella species by immunoblot
analysis using a monoclonal antibody specific for L. pneumophila IcmX protein. From these data, we conclude that the
IcmX protein is an essential component of the dot/icm secretion apparatus, and that a conserved mechanism of host cell parasitism exists for members of the Legionellaceae family.
*
Corresponding author. Mailing address: Section of
Microbial Pathogenesis, Yale University School of Medicine, Boyer
Center for Molecular Medicine, Room 354, 295 Congress Ave., New Haven, CT 06536-0812. Phone: (203) 737-2408. Fax: (203) 737-2630. E-mail: craig.roy{at}yale.edu.
Infection and Immunity, July 2000, p. 3971-3982, Vol. 68, No. 7
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Kim, W., Levy, S. B.
(2008). Increased Fitness of Pseudomonas fluorescens Pf0-1 Leucine Auxotrophs in Soil. Appl. Environ. Microbiol.
74: 3644-3651
[Abstract]
[Full Text]
-
Galka, F., Wai, S. N., Kusch, H., Engelmann, S., Hecker, M., Schmeck, B., Hippenstiel, S., Uhlin, B. E., Steinert, M.
(2008). Proteomic Characterization of the Whole Secretome of Legionella pneumophila and Functional Analysis of Outer Membrane Vesicles. Infect. Immun.
76: 1825-1836
[Abstract]
[Full Text]
-
DebRoy, S., Dao, J., Soderberg, M., Rossier, O., Cianciotto, N. P.
(2006). Legionella pneumophila type II secretome reveals unique exoproteins and a chitinase that promotes bacterial persistence in the lung. Proc. Natl. Acad. Sci. USA
103: 19146-19151
[Abstract]
[Full Text]
-
Nagai, H., Cambronne, E. D., Kagan, J. C., Amor, J. C., Kahn, R. A., Roy, C. R.
(2005). A C-terminal translocation signal required for Dot/Icm-dependent delivery of the Legionella RalF protein to host cells. Proc. Natl. Acad. Sci. USA
102: 826-831
[Abstract]
[Full Text]
-
Silby, M. W., Levy, S. B.
(2004). Use of In Vivo Expression Technology To Identify Genes Important in Growth and Survival of Pseudomonas fluorescens Pf0-1 in Soil: Discovery of Expressed Sequences with Novel Genetic Organization. J. Bacteriol.
186: 7411-7419
[Abstract]
[Full Text]
-
VanRheenen, S. M., Dumenil, G., Isberg, R. R.
(2004). IcmF and DotU Are Required for Optimal Effector Translocation and Trafficking of the Legionella pneumophila Vacuole. Infect. Immun.
72: 5972-5982
[Abstract]
[Full Text]
-
Zusman, T., Feldman, M., Halperin, E., Segal, G.
(2004). Characterization of the icmH and icmF Genes Required for Legionella pneumophila Intracellular Growth, Genes That Are Present in Many Bacteria Associated with Eukaryotic Cells. Infect. Immun.
72: 3398-3409
[Abstract]
[Full Text]
-
Ohnishi, H., Mizunoe, Y., Takade, A., Tanaka, Y., Miyamoto, H., Harada, M., Yoshida, S.-i.
(2004). Legionella dumoffii DjlA, a Member of the DnaJ Family, Is Required for Intracellular Growth. Infect. Immun.
72: 3592-3603
[Abstract]
[Full Text]
-
Rossier, O., Starkenburg, S. R., Cianciotto, N. P.
(2004). Legionella pneumophila Type II Protein Secretion Promotes Virulence in the A/J Mouse Model of Legionnaires' Disease Pneumonia. Infect. Immun.
72: 310-321
[Abstract]
[Full Text]
-
Ko, K. S., Hong, S. K., Lee, H. K., Park, M.-Y., Kook, Y.-H.
(2003). Molecular Evolution of the dotA Gene in Legionella pneumophila. J. Bacteriol.
185: 6269-6277
[Abstract]
[Full Text]
-
Edelstein, P. H., Hu, B., Higa, F., Edelstein, M. A. C.
(2003). lvgA, a Novel Legionella pneumophila Virulence Factor. Infect. Immun.
71: 2394-2403
[Abstract]
[Full Text]
-
Alli, O. A. T., Zink, S., von Lackum, N. K., Abu-Kwaik, Y.
(2003). Comparative assessment of virulence traits in Legionella spp.. Microbiology
149: 631-641
[Abstract]
[Full Text]
-
Robleto, E. A., Lopez-Hernandez, I., Silby, M. W., Levy, S. B.
(2003). Genetic Analysis of the AdnA Regulon in Pseudomonas fluorescens: Nonessential Role of Flagella in Adhesion to Sand and Biofilm Formation. J. Bacteriol.
185: 453-460
[Abstract]
[Full Text]
-
Robey, M., Cianciotto, N. P.
(2002). Legionella pneumophila feoAB Promotes Ferrous Iron Uptake and Intracellular Infection. Infect. Immun.
70: 5659-5669
[Abstract]
[Full Text]
-
Viswanathan, V. K., Kurtz, S., Pedersen, L. L., Abu Kwaik, Y., Krcmarik, K., Mody, S., Cianciotto, N. P.
(2002). The Cytochrome c Maturation Locus of Legionella pneumophila Promotes Iron Assimilation and Intracellular Infection and Contains a Strain-Specific Insertion Sequence Element. Infect. Immun.
70: 1842-1852
[Abstract]
[Full Text]
-
Tilney, L. G., Harb, O. S., Connelly, P. S., Robinson, C. G., Roy, C. R.
(2002). How the parasitic bacterium Legionella pneumophila modifies its phagosome and transforms it into rough ER: implications for conversion of plasma membrane to the ER membrane. J. Cell Sci.
114: 4637-4650
[Abstract]
[Full Text]
-
Nagai, H., Kagan, J. C., Zhu, X., Kahn, R. A., Roy, C. R.
(2002). A Bacterial Guanine Nucleotide Exchange Factor Activates ARF on Legionella Phagosomes. Science
295: 679-682
[Abstract]
[Full Text]
-
Higa, F., Edelstein, P. H.
(2001). Potential Virulence Role of the Legionella pneumophila ptsP Ortholog. Infect. Immun.
69: 4782-4789
[Abstract]
[Full Text]
-
Robey, M., O'Connell, W., Cianciotto, N. P.
(2001). Identification of Legionella pneumophila rcp, a pagP-Like Gene That Confers Resistance to Cationic Antimicrobial Peptides and Promotes Intracellular Infection. Infect. Immun.
69: 4276-4286
[Abstract]
[Full Text]
-
Rossier, O., Cianciotto, N. P.
(2001). Type II Protein Secretion Is a Subset of the PilD-Dependent Processes That Facilitate Intracellular Infection by Legionella pneumophila. Infect. Immun.
69: 2092-2098
[Abstract]
[Full Text]