Legionella pneumophila prevents proliferation of its natural host Acanthamoeba castellanii.
Legionella pneumophila is a ubiquitous, pathogenic, Gram-negative bacterium responsible for legionellosis. Like many other amoeba-resistant microorganisms, L. pneumophila resists host clearance and multiplies inside the cell. Through its Dot/Icm type IV secretion system, the bacterium injects more than three hundred effectors that modulate host cell physiology in order to promote its own intracellular replication. Here we report that L. pneumophila prevents proliferation of its natural host Acanthamoeba castellanii. Infected amoebae could not undergo DNA replication and no cell division was observed. The Dot/Icm secretion system was necessary for L. pneumophila to prevent the eukaryotic proliferation. The absence of proliferation was associated with altered amoebal morphology and with a decrease of mRNA transcript levels of CDC2b, a putative regulator of the A. castellanii cell cycle. Complementation of CDC28-deficient Saccharomyces cerevisiae by the CDC2b cDNA was sufficient to restore proliferation of CDC28-deficient S. cerevisiae and suggests for the first time that CDC2b from A. castellanii could be functional and a bona fide cyclin-dependent kinase. Hence, our results reveal that L. pneumophila impairs proliferation of A. castellanii and this effect could involve the cell cycle protein CDC2b.
Laboratoire Ecologie et Biologie des Interactions, Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, Poitiers, France.
Luce
L
Mengue
Signalisation et Transports Ioniques Membranaires, Université de Poitiers, CNRS ERL 7368, Poitiers, France.
Matthieu
M
Régnacq
Laboratoire Ecologie et Biologie des Interactions, Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, Poitiers, France.
Willy
W
Aucher
Laboratoire Ecologie et Biologie des Interactions, Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, Poitiers, France.
Emilie
E
Portier
Laboratoire Ecologie et Biologie des Interactions, Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, Poitiers, France.
Yann
Y
Héchard
Laboratoire Ecologie et Biologie des Interactions, Microbiologie de l'Eau, Université de Poitiers, UMR CNRS 7267, Poitiers, France.
Ascel
A
Samba-Louaka
D048248:Acanthamoeba castellanii / Q000235:genetics / Q000254:growth & development / Q000382:microbiology*; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D017489:CDC28 Protein Kinase, S cerevisiae / Q000172:deficiency / Q000235:genetics; D018797:Cell Cycle Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D048429:Cell Size; D004261:DNA Replication; D004926:Escherichia coli / Q000502:physiology; D006801:Humans; D016952:Legionella pneumophila / Q000502:physiology*; D018715:Microscopy, Video; D016296:Mutagenesis; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D017489:CDC28 Protein Kinase, S cerevisiae