Global Experts Meeting on Infectious Diseases
Tel Aviv University
Title: Listeria monocytogenes prophage turns itself into a molecular switch to support bacterial virulence
Biography: Anat A Herskovits
The human bacterial pathogen Listeria monocytogenes harbors a prophage within its genome, which is known to reproduce by both lytic and lysogenic cycles. We have previously shown that this prophage adopted an unusual behavior when L. monocytogenes infect mammalian cells. During macrophage cells infection the prophage, which is inserted within comK gene, excises its genome leaving an intact comK gene that is necessary to facilitate bacterial phagosomal escape. Prophage excision occurs preferentially within phagosomes, yet, unlike classic prophage induction, progeny virions are not produced and bacterial lysis does not occur. These observations insinuate a unique adaptation of the prophage to the intracellular life style of its host, demonstrating a mechanism by which the prophage turns itself into a genetic switch to support the virulence of its host. We are currently investigating the give-and-take interactions of L. monocytogenes with its prophage during mammalian cell infection, deciphering the molecular mechanisms that control its intracellular excision and maintenance. A search for phage genes that are specifically induced during macrophage cells infection and not during lysogenic of lytic conditions pointed out several genes and non-coding RNAs as regulators of the phage intracellular behavior. New data will be presented.